That's right y'all: non-standard Unicode characters are now (broadly) fixed on Linux. They're still screwed up for italic characters, though. Thankfully, italics are extremely rare in Island Off Outer Darkness, so, you shouldn't see that much (though it is in the first dialogue in the game, lol).
The fix has possible broad implications on text spacing throughout the entire game, and I have not replayed it since implementing the fix, so if something seems strange or different, report that to me! And NOT IN STEAM COMMUNITY, please, lemme know on one of my official social medias or my email. I like never check the Steam Community tab.
Full patch notes:
Fixes some Linux issues with the default fontset not including some unicode characters
Adds a setting to artificially set the game's completion status (only available when accessed on title menu)
Changed some settings language
Fixed the initial settings pop-up not having complete initial controller support on Steam Deck
Improved Extras menu behavior on controller when game is incomplete
Removed the ability to access the Screenshots folder from the Steam Deck's non-Desktop mode (as it would softlock the game)