Well… I might not be able to get the first three DMC games to run under Proton, but their latest game DMC5 runs almost perfectly. I’ve only played three levels, but so far it has been just as stable as it is under Windows. The only problem that I’ve found is that it has issues rendering FOV and background/foreground blur during cutscenes.
Graphical glitches aside; DMC5 has been just as impressive performance wise as the RE2 remake. Next time I play I’ll see how it handles recording and mods, though something tells me the latter will be identical in process to Windows.