I replaced my 3080 Ti with a 7900 XTX, reinstalled Tumbleweed to start fresh, and KDE on Wayland has been running great so far. Before, visual glitches galore, GPU refusing to output a signal if iGPU is not blacklisted, hardware video decoding outright does not work, etc.

Now, with AMD, I have not yet experienced graphics-related issues in weeks, fingers crossed.

Yeah it's absolutely ridiculous. The "stable" release is out in the extra-testing repo for Arch, and I just had an absolute nightmare trying to get it to work. Installed it, added the suggested nvidia-drm.modeset=1 nvidia-drm.fbdev=1 kernel parameters to systemd-boot, ensured all of the Nvidia kernel modules were present in initrd to do early KMS loading - tried to start a KDE Wayland session and the desktop ran no more than maybe 5 FPS and I wish I were exaggerating that. A very similar issue was reported on their forums but the error I'm getting from kwin_wayland_drm is slightly different.

Tried install GNOME, but its Wayland session wouldn't even launch at all. Loaded into its X11 session and it seemed to not be using accelerated graphics whatsoever.

Now of course, part of the blame goes to me for opting into the testing repo... but at the same time, I shouldn't have to go through those hoops just to potentially get a working Wayland desktop (and I suspect even if I had succeeded, the same issues will have still been present). As far as I understand, AMD/Intel's drivers are just part of mesa and are included in the kernel - no modifying your initrd, no worrying about DKMS, no trying to mess with .run files...

I have a Windows partition on one of my SSDs for the few occasions that I need to do something that can only be done from Windows, and I think I'm just going to use that till my GPU comes in. Funnily enough, Nvidia's drivers aren't even that great on Windows either - I still get a screen flicker issue whenever (I believe) the power state of the GPU changes, so for example playing a YouTube video, or even Steam popping a toast notification saying that a friend has launched some game. And plenty of my friends have tales of nightmares with trying to install and manage the Nvidia driver on Windows.

I would've never bought an Nvidia GPU in the first place if I had known how bad it was on Linux, and my current Nvidia GPU (a 2080) wasn't actually purchased by me, but handed down by a very gracious friend at the beginning of the year since times have been really tough for me. Thankfully this last month I was able to put in some extra hours to be able to set aside some money for a used 6700xt because if I have to deal with this any longer I'm going to lose my sanity.

Ah very nice, a 7800 XT should be a fantastic upgrade (assuming my understanding of AMD's GPU lineup is correct, I can hardly keep up with Nvidia's as a "software" guy)! I'll be keeping my fingers crossed that it gets there quickly for you, and that the swap goes smoothly.