

I think realistically the best option is to stick with an older version of KDE until your issues get fixed upstream or switch to another DE.
Anyone technically literate enough to port KDE back to X11 is likely also literate enough to fix the blocking bugs.
… Unless they’re doing it purely on ideological grounds, which is probably not a healthy way to run a project.



Valve has put a lot of work into it, so unless you want to play hypercompetitive shooters (which ban Linux as a scapegoat for how hacker infested they are), most games will just work. Installing Steam should just set things up automagically for Steam games.
If there’s a game you’re actively curious about, you can look it up on https://www.protondb.com/ to see what other people say about how well it works.