https://bugs.winehq.org/show_bug.cgi?id=53673
--- Comment #4 from NM64+bugs.winehq.org@PM.me --- Yep, seems to be working now.
Interestingly, the program seems to no longer like working when there are unicode characters in the path, e.g. "アプリケーション" (without quotes); I'm pretty sure that worked back with wine-staging 7.13 but I can only test with it on a different OS installation altogether which, for this unicode issue, has me wonder if it's even a wine issue at all (though I have other wine applications that run without issue even if "アプリケーション" without quotes is in the path).