is there any way to make firearms work in a fantasy setting alongside swords and armor and stuff?

Armor and firearms already historically coexisted — the famous knightly suits of full plate in the 15th and 16th century were typically "proofed" by being tested against shots from early matchlock and flintlock guns, and although full-body armor got less useful to have as firearms' penetration increased, metal armor did not disappear entirely until the 19th and 20th centuries. (The common soldier of the early modern period wasn't full-body armored, of course, but neither was the common soldier of the medieval period.)

Magic is arbitrary and you haven't specified very much about what it can or cannot do, so I'm going to set it aside. A world where some people ride on horseback with metal breastplates, swords, and handguns is very easy to envision, because it was ours for quite a long time.

Video games do this all the time. There are numerous ways to make firearms comparable to other weapons.

Inaccuracy

Smooth-bore guns were known for being useless at longer ranges. In the American Revolution, solders were told not to shoot at anything more than 150 feet away because they were wasting bullets. That's where the "whites of their eyes" adage came from.

Unreliability

Before mass production became a thing, you had to go to a gunsmith if you needed to replace part of your gun. Precision machining was unknown, and sketchy metallurgy meant that your gun might not stay working for 100 shots before you needed to get it repaired. Misfires were common before we developed ammo with shells, and the need to have a person carry around raw gunpowder meant that the quality of the gunpowder wasn't guaranteed.

This is compounded if you live in a world of magic. Magic tends to be all about warping the laws of physics, and precision machines are generally incompatible with them. One tiny little warp in time-space can make a gun explode in your hand. As such, a gun owner would have to familiar with what they have to do with a gun to compensate for this.

Maybe they can't have the tight barrel tolerances, so you don't get as much pressure pushing the bullet forward. Maybe you have to re-align the mechanisms between each shot. Maybe a gun requires a magic compensation device that takes a bit of skill to keep working. The entire effort might make using a gun similar to using a 3d printer last decade. More trouble than it's worth unless you're really into it.

Low power

We think of bullets as things that'll punch through almost any armor. This isn't necessarily the case. Variations in how physics work in your world might result in armor that can resist bullets, or bullets that don't hit as hard. An arrow in our world has roughly the same energy as a .22 pistol bullet. If your people are heroically strong, however, or your bows are magically enhanced, then maybe they can get more energy into a bow shot than you can safely pack into a pistol.

Noise, smell, and smoke

These are things that we never notice while playing a game, but they're significant in the real world. In the Napoleonic wars, rifles had roughly the same lethality as longbows because they filled the air with smoke. Use of guns indoors on a regular basis will result in hearing loss, and you can't do it without attracting attention.

They're rude

Have you ever had a teammate jump your case because you're doing something that they don't see the benefit of? This might be especially true if it's something that could alert the enemy, ruin your team's hearing, and is just plain stinky.

• No industry to produce standardized cartridge cases.
  The lever actions you mention rely on having cased cartridges with remarkably tight manufacturing tolerances by pre-industrial standards. A watchmaker might be able to manufacture them, but who can pay watchmakers to produce enough ammo? It also helps if the weapon uses percussion primers, which require good chemistry.
• Reduced reliability, compared to cold steel.
  Without those cartridges and primers, you are left with something like a muzzle-loading rifle or musket. Those might have flintlocks, wheellocks, or matchlocks. Whatever they technology, there is a good chance that they will not fire when the trigger is pulled, and it gets worse in rain.
• Inability to carry them loaded.
  Another consequence of the lack of modern cartridges is that one cannot load a weapon at the start of the week and expect them to fire a few days later. Swords need care, too, but a sword with a few rust spots is still lethal.
• A low number of ready shots would not keep them back.
  Plenty of wars have been fought with single-shot rifles, like the Martini-Henry.
• Part of the reason why muskets replaced bows was ease of use.
  At the time when muskets replaced longbows or composite bows, a skilled archer had similar lethality, similar range, superior accuracy and superior rate of fire. But as the proverb went, to get an archer, start by training his grandfather. Musketeers were easier to train.

How can magic help?

• Alchemists come up with a compound that will reliably burst into flame if and only if it is given a sharp jolt (a percussion cap, in effect). Either it is alchemy or it is mundane chemistry helped by their experience in the lab.
• Enchanted firearms do not jam even if a mundane mechanic would expect them to jam because of ill-fitting cartridges, weak springs, and so on. How? That's magic. At the extreme end, a pistol might reliably use a rifle cartridge, and vice versa, when a simple size comparison says they cannot possibly fit.
• Or, the other way around, cartridges are magically 'polished' to have exactly the right dimensions, even if the artisans only got them approximately right. Either approach may be used, or they may be combined to get firearms actually more reliable than their real-world counterparts.
• The gun or the powder might be magically weather-proofed. An enchanted priming pan keeps the powder dry, or enchanted powder fires even when wet.
• Taking a completely different path, a gun lock might be enchanted to produce a brief spark inside when a lever is pressed, a magic word is said, or a magic thought it thought. That means a muzzle-loading firearm might have no moving parts, and no openings at the rear end. No need to worry about priming powder in the pan, and it might be practical to carry it loaded -- insert the powder, a wad, the bullet, and a wax seal, and that should hold some time.

So what does that mean?

• You can have matchlock or flintlock muskets for relatively large infantry armies. They fire lead balls which do not exactly fit the barrel, that's why ramrods are called ramrods. Either each musketeer has a mould to cast bullets, or they are reasonably close in caliber.
  Say that is typical for "orc" or "human" armies. Meanwhile "elvish" armies still use their bows, and get better performance out of them than the orcs get out of their muskets.
• Individual adventurers may perhaps carry a wheellock pistol in addition to a sword, or woods runner characters may have a flintlock rifle instead of a bow. A well-made and carefully loaded rifle may be able to hit at better ranges than a bow, but that comes at the expense of the rate of fire.
• Wealthy or technologically progressive characters may carry multi-barrel pistols or perhaps even revolvers. These are not immediately ready after being drawn from a holster. As a minimum, the shooter would have to open pans or something like that.

There is already a number of excellent suggestions, I'd like to suggest a slightly different line of reasoning centered on training and accessibility.

Specifically:

• Anybody can fire a firearm, and most anybody should be able to reload it.
• Upper body strength is required for bows and crossbows, which means regular training.
• Extensive training is required for swords & magic, so much so that only professional soldiers, adventurers, or the wealthy can be reasonably expected to have the time to do so.

With that in mind, the answer is relatively obvious:

• "Weak" firearms are the weapons of the unwashed masses.
• Those with training favor bows/crossbows/swords... in combination with magic.

To make this work:

• Firearms have a relatively short range: without precision machinery, there's a loss of pressure in the uneven rifle.
• Firearms have relatively low accuracy: such as real-world smooth bore guns.
• Firearms have relatively low power, compared to a magical arrow, so that magical armor or protections can deflect most bullets. But not cannon balls, of course.

And there we have it!

You end up with a relatively similar scenario to peasants & knights in a medieval army, where peasants were numerous but individually posed no threat to a well-armored (and mounted) knight in full armor, so that battles involve matching peasants vs peasants (to control ground, and keep your camp) and knight vs knight.

As a twist, you can add some "elite" adventurers/nobles/merchants with very expensive precision firearms and the training to make deadly use of them, which the other elites look down upon (it's the weapon of the masses, meh) while they are in fact quite effective.

I have been struggling to make swords useful along side guns. The only difference being that i needed to make them useful along side weapons like assault rifles and similar modern technology. Though there have been some methods i have seen that work in these circumstances.

Guns are more expensive

One of the best ways to to not make guns dominate literally everything is simply making using swords more economically viable.

• Your world might not have industrial products of guns. Compared to swords they could be much harder to produce which would make them a lot less common and there for more leave room for other weapons.
• Bullets could be expensive and your world simply might not be able to produce them at large scale.
• Guns might be only be able to be manufactured by a few experts and enchanting them could be even harder. Which would make them incredibly expensive and not a thing you put in the hands of every infantrymen.
• There could also simply be better alternatives like maybe you easily enchant a sword to thrown like a boomerang or something similar.

Protective Magic

Then there is also the possibility of using magic to block bullets.

• Magical force fields could be common and can easily block just enough bullets to make breaking it impossible with a single salvo.
• Similar to the last one maybe mages could protect whole armies from bullets for a short time. In that regard maybe because you can shoot more arrows in a shorter time they could destroy the barriers.
• Magical super metals could just deflect bullets making a knight in such a amor able to just slay a defenseless gunman.
• Additionally this armor could just like some in our world just be priced by a sword more easily. This happens because swords are sharp and can pierce some materials easier than a more blunt bullet.

Screw guns up with magic

Guns may be more susceptible to magic than swords or other more simple weapons are.

• A fire spell could just blow up the gunpowder prematurely and make you think twice about using a gun a your primary weapon.
• A water spell makes the gunpowder unusable leaving you with more reliable methods.
• A wind spell can just make the bullets just miss a target.
• Guns have sensitive parts that magic could screw up a sword on the other hand works just fine even when thrown in the mud.

Note: English is not my primary language so please don't judge me hard on my horrible grammar and spelling

Dune has a really subtle and neat way of making swords relevant when guns exist. Everyone has their own personal shield which blocks projectiles moving at a dangerous speed. I'd watched the movie several times and this didn't click with me until someone on YouTube pointed this out.

You can argue that the 'shield' is somewhat magical but it does have the effect of changing the material conditions of the world in such a way that learning sword craft makes sense.

Not sure if it might be useful, but you can get an example of this in the Mistborn series, written by B. Sanderson (fourth book and after, first three books are in a medieval setting) where it is combined the magic system (hard magic system) and use of fireweapons.

In that system, some of the magic users can push away metallic objects, so when they perceive a metal object they can repel it from themselves (slow a bullet that comes towards you, or give an extra impulse to a bullet) while others can do the opposite (attract a bullet to themselves to prevent going from someone unarmored) among other types of magic. Perhaps, it provides with an idea of how to balance a magic world with guns.

One simple way to ensure that swords continue to be used alongside guns that historically drove them from the field is to make them magically useful.

Perhaps in order to enchant your weapons, you must enchant the part that hits the foe, and there's no mass enchantment, the weapon needs an individual spell. If you want to kill the werewolf, you must meticulously enchant every single bullet -- or just one blade. Or possibly a set of arrows, but the thing about arrows is that you can retrieve and re-use a high proportion of the time.

Therefore the rule is guns for mundane, swords for magic. REALLY dangerous monsters/wizard may need magical bullets, and REALLY rich people may use magical bullets against ordinarily magical monsters, but those are exceptions.

Other such conditions could also work

If you want some inspiration from existing fantasy works, just look at Star Wars. It's supposed to be set at a technological level that is in our future. Guns are the most commonly found weapons everywhere. And yet the one military force that usually trumps everything else in the galaxy is psychic monks with magic swords.

But better than that is real life. When guns became a thing in the battlefield, they did not immediately make melee weapons obsolete. That took centuries.

Myamoto Musashi died in 1645. Before his death, he wrote this about guns:

From inside fortifications, the gun has no equal among weapons. It is the supreme weapon on the field before the ranks clash, but once swords are crossed the gun becomes useless.

And indeed, a hundred and something years later and on the other side of the world, the Golden Age of Piracy was happening. People fought with handheld guns and cannons, but swords were still a thing in the battlefield.

So you see, as long as technological progress in your world happens at the same pace as in real life, you may have 200 to 400 years in which guns and swords cohexist without much issue.

Swords are melee weapons and firearms are ranged weapons. The 2 don't share the same role on the battlefield so one can't replace the other.

Armor has always been used so it won't dissapear in it's entirely. How extensive its usage will be will depend on its required capabilities, the fashion of the fantasy society in question, and how many resources the buyer of military equipment is willing to expend in that particular area. That's something you'll have to decide on as its your fantasy(I presume).

If you don't wan't dedicated melee troops(of all types) to be obsolete in your world then the firearms cannot be breachloaders, just muzzleloaders. So your repeater(and presumably more common single shot breachloaders) would have to be too rare to be used as a standard weapon.

That's all assuming you want the non-magic weapons to function the same as in the real world, which you really don't have to if you don't want it to be like that. It's your world so you can have things work however you want.

The necessary ingredient of gunpowder is sulfur. Assume that your world has NO sulfur at all, except one bound in living creatures, or small amounts only found in the Underworld.

Instead, the explosive used in firearms is Werewolf blood. A sliver primer in the firearm pierces the charge and causes the werewolf blood to instantly burst into flame, expelling the bullet.

However, only wizards have the magical skills to extract werewolf blood without killing one, so they fully control the supply of "fireblood" needed for firearms.

Guns are very, very deadly, reliable and effective, but each explosive shell costs more than its weight in gold, so gunslingers tend to be wealth and use them sparingly.

Gremlins

In the spirit of Discworld - Perhaps there are (magical) creatures that inhabit mechanical devices with springs, levers, etc. There are ways to repel them but they are costly or unreliable. The more complicated the device, the more the gremlins like to mess with it. It's one thing if your clock stops working or lock gets stuck, another if your gun explodes in your face. There could be amulets worn by gun users to ward off the gremlins, enchantments to protect weapons, curses and counter curses used by rival forces. Armies could try to infect rival camps with gremlins to destroy their weapons. This results in an arms race between the gremlins and the mages, with the gremlins always finding ways to get around a guns protections. Simpler devices like crossbows could be less appealing to the gremlins, or the consequences of their failure less dire.

Additionally, the more guns there are, the more likely the gremlins are to find them, infest them and spread. One gun in a unit may be safe, but an entire unit of rifleman is inevitably going to be infested.

In a similar vein gun powder could be the preferred food of a (magical) pest and extreme effort needs to be expended to protect it from infestation.

You kind off wrote yourself into a corner with your premise.

If the setting's "most powerful" individual firearm is a repeating rifle with smokeless powder cartridges, then that implies single-shot breech-loaders are the norm. With the most "up-to-date" militaries considering transitioning to repeaters in the near future.

Once your troops can get a plural number of aimed shots off against a running enemy from within 100 meters, the melee troop in question is no longer worth the effort.

Once rifles that can be loaded and fired with an aimed shot within 10 seconds become the standard, this happens to dedicated melee cavalry the majority of the time(outside of suppression by supporting rifle users).

Flintlocks loaded with paper cartridges allowing 3 aimed shots per minute already made melee infantry not worth the effort by the 1700s, regardless of potential niche applications.

Bows, crossbows, and other ranged weapons were rendered unviable for ranged combat by matchlocks that allowed for 1.5 aimed shots per minute.

With magical enhancement this process could be accelerated in your setting compared to real world Europe. Magic could make breach-loading(potentially multi-shot) firearms with smokeless powder cartridges become standard in this setting's equivalent of its Early Modern Era instead of its Second Industrial Revolution. Maybe even caseless ammunition in its version of the Great War. And that's just personal firearms.

Magic can make various concepts practical for usage at scale during earlier stages of technological evolution than they were in real life. Unless you make the benefits of magic just not apply to firearms, but still have cold weapons benefit for rather arbitrary reasons(which you clearly don't want).

But that's just how I think and you don't have to do it like that. Make the fights in your setting work however you want for whatever reasons you desire. It doesn't need to be "realistic."

How we dealt with firearms in a D&D campaign I was a part of was we made them exceptionally powerful but also extremely expensive. Our argument was that despite metalworkers being exceptionally skilled at making bladed weapons, they hadn't perfected the mass manufacture of reliable pressure bearing firearm components such as barrels so each one was labor intensive to make and thus expensive.

We also made it so ammunition was hand made and the ingredients scarce. Just like real blackpowder it required 3 different components that could be bartered for or produced. Slugs also had to be casted by hand. Then these could be combined before a battle or during downtime into "paper cartridges" which were ready to use at any time.

For cased ammunition we just made it expensive but you could reload it yourself for much cheaper. Guns that used cased ammunition were status symbols for people with alot of wealth, they were often masterpieces with engraving and such.

Sounds like alot of work right? It was, but the blackpowder in our universe was kinda magic infused so each shot did a significant amount of damage even at early levels. I distinctly remember taking the head off a goblin from some distance in one shot which was quite satisfying.

If guns can be enhanced by magic, then so can armour and swords!

So, armour can be enhanced to make it bullet-proof, swords can be enhanced to make them be able to somehow defeat the bullet-proof armour, but the massive effort in enchanting every single bullet so it can pierce the otherwise bullet-proof armour would be too much.

Boots can also be enchanted so that melée units can run very fast and very quickly close the distance to the ranged riflemen, thereby quickly nullifying the range advantage of rifles.

Imagine a feudal world, where fighting remote is considered dishonorable. Arrows, bullets, firearms - they are all disgusting. Even if they tend to win, the users and usage, are outright chastised.

Impure, despicable, untouchable castes of mercenaries are responsible for the muder at a distance. And it can happen, that the noble-man/samurai of your own side, turn on your "hired honorless" together with the remains of the other sides knights caste, turning it into a literal class warfare battlesite.

The gunusers would be shunned, forced to camp in a seperate camp, fetching water downriver, with a baggage (train), bundled together with the leppers, the cesspit-workers and other despised. So strong could the despise be for the "cowards" that society expects the sniper to debowel him/herself, once he/she kills a "noble" man on horse or a wizzard. The pay would have to be good, for anyone to consider this job.

And of course, there would be those, who would try to escape societies taboos. As in roving armies with guns, testing the caste structure at the limits of the known world for weaknesses, slowly taking the old world apart.

There would be a inquisition hunting the supply chains of guns - to prevent them from "Rolling pure swoards into poison pipes" - but then just cultural taboos wont cut it. The reason why japan never had more guns - was the lack of iron needed for that endavor. That could be a limiting fact of your world too, preventing firearms from taking over.