By some miracle, using SteamTinkerLaunch, I've got Flawless Widescreen working to the point where it's not crashing the game. It's not applying the fix either, though.
there is an alternative method to install fedora silverblue or kinoite (depending if you want GNOME or KDE) and rebase, but that requires more steps that will have to be done afterwards
So having issues with wayland plasma I decided to try x11 plasma only to encounter an entirely different problem. Full screen games mouseable area is blocked for like a quarter of the left side of my display.