How to get smoothly running emulator games with free software only on Debian/KDE with a Nvidea GeForce GTX graphics card?

I'd like to play games on my computer with free software only. The graphics card driver should hence be free software too. I currently have a Nvidea GeForce GTX graphics card and thought about getting a new graphics card after selling it but to date couldn't find a simple list of benchmarked/compared graphics card that are confirmed to work with FOSS drivers under GNU/Linux (asked about it) . The best free driver for Nvidea graphics cards seems to be Nouveau and the graphics card I have is listed here under Code name 'NVE4 (GK104)' which is under Family 'NVE0'. According to this feature matrix , family NVE0 should be relatively well supported. (This also means it doesn't make much sense trying to swap the graphics card if things are supposed to work with that one.) However, it has many glitches and the emulator games I tried didn't work better than just the onboard of mainboard 'B250 PC MATE' as I described in this question . Maybe I installed it the wrong way, needed a newer version of Debian², needed to use Wayland instead of X11³ or missed installing something else such as some Vulkan-related packages. -> **How to get smoothly running emulator games with free software only on Debian/KDE with a Nvidea GeForce GTX graphics card?** If there are problems using the graphics card specifically for emulators on GNU/Linux with Nouveau (as suggested in the other question), which emulators are supposed to be compatible?4 Do I need to install or configure any additional things to a) prevent these glitches and b) make use of the graphics capabilities for emulators? --- ² now running latest Debian 11 stable (xserver-xorg-video-nouveau is v1:1.0.17-1 and KDE Plasma is v5.20.5) ³ I recently switched to Wayland despite the many bugs with it in Debian/KDE because beyond security-improvements it prevents screen tearing allowing me to properly watch videos 4 I tried the emulators Dolphin, PCSX2 and PCSX3 for Wii, PS2, PS3 and GameCube games within Lutris. Some of the games do work but have graphics-problems such as running only very slowly (including the audio).