so I've recently learned about sudoedit and how I can edit a file more safely than the standard "sudo vim".
the problem is now, when I'm in vim and "vsplit" or "tabnew" I open it as my user account (no root privileges)
sudoedit launches a separate instance of Vim, because it has to manage the lifecycle of the editing session; i.e. write back the edited temporary file with root priviledges. It cannot achieve that from a running Vim session.
However, there are plugins that achieve sudoedit-like functionality, for example the aptly named SudoEdit.
:vsp sudo:///filename. (I don't use this functionality and just kept it for backwards compatibility)
sudoinsudoedit filenameonly works forfilename; the whole point ofsudoeditbeing to allow you to edit protected files from your regular account.