I have a laptop with a nvidia card and nothing works. From the installers crashing, windows freezing, full desktop freezes, awful performance, awful battery life under Wayland, every glitch under the sun from minor lines appearing on the screen to potentially physically damaging glitches like rapid flickering, and every other issue you could possibly imagine: it happened.
I mean it happened in like the week total combined that I was testing GNOME/KDE. Probably if I spent any more time on it my computer would explode?
Meanwhile X11 with i3 just fucking rocks. Smooth and stable like nothing else.
My only issue is, ironically enough, also with multi-monitor setups, where the layout and main monitor selection seems unstable and sometimes changes when waking up from sleep. I've been following KDE's development (through Nate's incredible blog[0]) and I'm pretty sure these problems have been fixed with the new 6.0 release.
But yeah, you seem to be particularly affected by bugs, sorry for the experience. What Nvidia card do you have? And driver versions?