Be aware on kde with wayland that ps2 doesnt play nice with open windows in the background, for me anyway. I have to minimize anything else i might have open or suffer stuttering and frame drops.

Also yes to protondb.

I am actively playing Warframe, Planetside 2, Deep Rock Galactic, Darktide, Elden Ring, Team Fortress 2, and Minecraft (through Prism launcher flatpak)

The only game that does not work that i wish did is Vermintide 2.