The native version installs, runs, saves, loads, and everything, but there were very frequent UI - and only UI - glitches that occured while navigating it (e.g. going down or up to the next entry in the guild menu, or the action menu during battle, etc). Glitches included showing older UI instances (e.g. it would show arrow pointing at previous action plus its description, despite selecting the next action) and graphical corruptions (corrupted sprites and text), all persist until I force an update by moving the selector (moving to the next skill, menu item, etc). These glitches happen every third or fourth UI update. Playing around with the vsync settings through the config file and forcing glcore and opengl through launch commands yielded no improvements (the launch commands caused the game to crash at startup, however).

Enabling Proton (9.0-4 being the most recent, as of this writing) makes it run without any issues. I had to copy the saves manually to the prefix, however. Steam Cloud sync didn't bother doing so.