Its not nearly as bad as people make it out to be. I do think its distro specific. PopOS was rock solid with nvidia drivers. I had a 3070ti that worked really well with it. I ended up getting a 6700xt because I wanted to go full-tilt into linux land and everyone raves about the open source amd drivers. I figured if I was going to be all-in on linux, why not get a radeon card.
I traded some minor issues for some fairly significant limitations. Nvidia had stutters every once in a while on the desktop. Like maximizing a window would occasionally (1 time in 50) 'hang' for a half second then complete. For Apex Legends, there was a semi-manual step to pre-cache shaders to prevent stuttering in the game. That was actually fixed over a year ago with a proton and steam update. That was about it. It also ran everything else flawlessly.
When I switched to Radeon, I thought it would be smooth sailing. Its really just different issues. You obviously dont have the nvenc encoder. The radeon encoders all suck, but AMF, their new hottness, is supposed to be really good. Well, you can't use that with the open source mesa drivers that everyone raves about--the big draw for using radeon on linux to begin with. You have to use the proprietary ones if you want to use AMF. Cool, but if you do that your game performance can suffer because the amd proprietary drivers aren't as good as the mesa ones. Oh, and you can get occasional stutters on your desktop...
You can't mix and match so if you want to stream your games on twitch or record your gameplay, tough shit. Get used to throwing CPU cores at VAAPI.
Also, AMD absolutely sucks when it comes to AI/ML. Cuda is king and ROCM is trash. If you are doing anything with AI/ML stick with nvidia. I literally bought a used 1080ti and threw it in my server (ubuntu) to do some AI jobs, because I got tried of fighting with radeon, trying to get rocm to work.
All that said, my next build will very likely include an nvidia card --even though I plan on running linux exclusively.