How to run .net 8.0 and angular at the same port?

I have a web application. I'm using Angular 18 and .NET 8.0. I would like to run both at the same port.

package.json:

{
  "name": "WebAplication.WebUI",
  "version": "0.0.0",
  "scripts": {
    "ng": "ng",
    "start": "ng serve",
    "build": "ng build",
    "build:ssr": "ng run WebAplication.WebUI:server:dev",
    "watch": "ng build --watch --configuration development",
    "test": "ng test"
  },
  "private": true,
  "dependencies": {
    "@angular/animations": "^18.2.0",
    "@angular/common": "^18.2.0",
    "@angular/compiler": "^18.2.0",
    "@angular/core": "^18.2.0",
    "@angular/forms": "^18.2.0",
    "@angular/platform-browser": "^18.2.0",
    "@angular/platform-browser-dynamic": "^18.2.0",
    "@angular/router": "^18.2.0",
    "bootstrap": "^5.3.3",
    "ngx-captcha": "^13.0.0",
    "rxjs": "~7.8.0",
    "tslib": "^2.3.0",
    "zone.js": "~0.14.10"
  },
  "devDependencies": {
    "@angular-devkit/build-angular": "^18.2.6",
    "@angular/cli": "^18.2.6",
    "@angular/compiler-cli": "^18.2.0",
    "@types/jasmine": "~5.1.0",
    "jasmine-core": "~5.2.0",
    "karma": "~6.4.0",
    "karma-chrome-launcher": "~3.2.0",
    "karma-coverage": "~2.2.0",
    "karma-jasmine": "~5.1.0",
    "karma-jasmine-html-reporter": "~2.1.0",
    "typescript": "~5.5.2"
  }
}

launchSettings.json:

{
  "$schema": "http://json.schemastore.org/launchsettings.json",
  "profiles": {
    "WebAplication.WebUI": {
      "commandName": "Project",
      "dotnetRunMessages": true,
      "launchBrowser": false,
      "applicationUrl": "http://localhost:5000,https://localhost:5001",
      "environmentVariables": {
        "ASPNETCORE_ENVIRONMENT": "Development"
      }
    }
  }
}

appsettings.json:

{
  "Kestrel": {
    "EndPoints": {
      "Https": {
        "Url": "https://localhost:8000",
        "Certificate": {
          "Path": "",
          "Password": ""
        }
      }
    }
  }
}

Program.cs looks like this:

using Microsoft.AspNetCore.SpaServices.AngularCli;

var builder = WebApplication.CreateBuilder(args);

builder.Configuration.AddJsonFile("appsettings.json", optional: false, reloadOnChange: true);

// Konfiguracja serwera Kestrel
builder.WebHost.ConfigureKestrel((context, options) =>
{
    options.Configure(context.Configuration.GetSection("Kestrel"));
})
.UseKestrel();

builder.Services.AddControllers();
builder.Services.AddHttpClient();

var app = builder.Build();

app.UseStaticFiles();

if (!app.Environment.IsDevelopment())
{
    app.UseSpaStaticFiles();
}

app.MapControllers();

app.UseSpa(spa =>
{
    spa.Options.SourcePath = "ClientApp";

    if (app.Environment.IsDevelopment())
    {
        spa.UseAngularCliServer(npmScript: "start");
        spa.Options.StartupTimeout = new TimeSpan(0, 15, 0);
    }
});

app.Run();

I try to start with https://localhost:8000, unfortunately it doesn't work. There is no issue information and the page is not loaded. When I just use ng serve in ClientApp, my Angular app is loaded and it works. What did I wrong here?