I’ve never had this as an issue with KDE. Do you have the command for prime render offloading on the Steam launch options? I usually launch my games through Lutris and it handles that pretty well.
The one the Gnome team is working on right now, as described here.
The basic premise of rearranging windows at an optimal size, without stretching them out to fill fractions of the screen, seems like the perfect medium between floating and tiling.
I second the recommendation of Go. I’m very much a beginner, but the subtlety and variety of every game kind of ruined chess for me.
Some more recommendations of learning or beginner resources:
Go Magic has a lot of really in depth video and interactive tutorials. There’s a paid plan, but the beginner and early intermediate courses are free and way more thorough than anything else online right now.
The Conquest of Go is a great little game on steam that has its own tutorials and a campaign mode with scaling difficulty. It’s my favorite way to play against bots, but you can also connect your OGS account and play online through there.