Recent testing revealed that Arch Linux, Pop!_OS, and even Nobara Linux, which is maintained by a single developer, all outstripped Windows for the performance crown on Windows-native games. The testing was run at the high-end of quality settings, and Valve's Proton was used to run Windows games on Linux.
Nvidia isnt so bad if you’re on a stable distro it supports and using x(though Ive heard wayland support is improving for it). On rolling or more cutting edge distros where the kernel is likely to change every few weeks and major DE versions might ship that proprietary driver will hurt.
That said while amd is generally better on linux for this reason it’s worth mentioning that it has two huge flaws:
1.Its not perfect like the fans mention. As someone who owned a 3500u and 6650u apu life under amd isnt always sunny. 3500u had a kernel regression for about half a year that prevented the cpu from idling and rembrant apus have an issue where the whole system locks up which seems to come and go(feels like it’s gone for now but Ive thought that before). Desktop gpus are better, but they still did suffer from driver bugs. I think my experience with my 5600xt was better than windows fans had for that generation, but it was not entirely stable and I did suffer from many kernel panics and system freezes. A few mesa and kernel releases fixed that, but it wasnt perfectly smooth. In addition to that no hdmi 2.1 support which is fine unless you game using your nice oled tv because no tvs come with display port. Proprietary drivers do allow for supporting some of the more obnoxious features that arent allowed.
So while there is a lot of pro amd comments in the linux world and its worth acknowledging that the open source drivers are generally good it’s not perfect and the grass isnt always greener.
Just from that comment we can see how far from mainstream adoption Linux is for gaming… You really need to want to understand how things work to fix things that might not work natively. Not every gamer wants to be super knowledgeable about computers, most just want to play games. Heck, I’m very good with computers and I know that what little time I have to play games I don’t want to spend trying to make them work…