It's possible that some of the issues I ran into were due to Manjaro not being Ubuntu, but they could also have been due to drivers or some random setting somewhere in the system.

Plenty of people on protondb reported zero issues with the same games on their Manjaro/Arch boxes.

> Playing games on Windows often requires fiddling as well. Either having to lock the mouse to one monitor, fiddling with V-sync and FPS limits (often only possible through graphics card drivers, launch arguments or text config files), disabling Windows malware scanning, fiddling with Windows compatibility settings for older games

Maybe it's the type of games I play, but this is extremely rare in my experience. I don't remember the last time I had to fiddle with anything outside the game's own settings despite having a multi-monitor setup.