The difference between most distributions can be summed up in plumbing (irrelevant as far as you're concerned) and frequency of updates. They'll have different package managers (all of which could be told to "install this" or "uninstall that"), and slightly different versions of software available (some newer, some older). So, stick with what you've got. You may decide to switch one day, but you should do it for a compelling reason (e.g. "I like the philosophy behind this project") rather than something superfluous (e.g. "this one thing is broken, maybe wiping my hard drive and starting from scratch with a different distribution will make the problem go away.")

Video on Linux can be a bit confusing, because there are a lot of moving parts. If you have a modern AMD card (up to somewhere around 10 years old), it should be supported by the amdgpu driver, which is part of the Linux Kernel and should be included out-of-the-box in any distribution. The driver is probably working fine. The graphics libraries (Mesa3D in the case of AMD cards, this provides the OpenGL / Vulkan APIs used by games and graphics software) are probably also fine.

There are two major display technologies present on Linux. X11, and Wayland. X11 is the classic method, with a lineage running all the way back to 1987. Wayland is a newer system, introduced in 2008, but only gaining traction somewhat recently. Your desktop environment (KDE Plasma, Cinnamon, Gnome, etc) ultimately needs to use either X11 or Wayland to put graphics on your screen. Over the past decade, there has been an ongoing migration. Many distributions default to Wayland unless there is a good reason not to. Considering your hardware, you are probably running a Wayland session. You can check by running echo $XDG_SESSION_TYPE in a terminal.

Xrandr is a tool for configuring displays on X11, if you are running a Wayland session, it probably won't work correctly. A lot of distributions still allow you to choose an X11 session in the display manager (the graphical log-in screen).

I'd recommend you test Bazzite, Nobara and Solus and see which one you like best.

As far as I know screen resolution issues usually comes down to outdated drivers and/or kernel, at least for newer hardware. Using a distro that's very up-to-date usually solves that, any of the 3 ones I cited above are regularly up-to-date.

I'll briefly explain the differences between them.

I'm an experienced user but I wanted something like this for my desktop PC for switching from windows and I'm really liking Nobara. it's got a KDE edition too. some nice out of the box GUI tools for installing GPU drivers/game compatibility tools is handy. I think it ships with game ready drivers for AMD so you'd be set in that department. can't speak on resolution stuff but I know KDE supports it and if it is a driver issue Nobara should make it go away.