I’ve been daily driving niri on my gaming PC for about as long as you’ve been away. The only problem I have now and then is games will run in tiled mode, while the game itself is fullscreen, so I’m only seeing the left half of the game. Mod+Shift+F has always fixed it so far, and it’s rare enough that I haven’t looked into making a window rule. I don’t use Steam but I’m not sure that matters.