Sorry my reply is so slow >.< I was away from home for a little bit and just really not doing so great with my mental health at the moment.
The only other thing I can think to do besides sending the dev build, which I just don't have the mental energy to build, send, and then analyse the logs at the moment, is to maybe delete your save data completely in case something at some point somehow bugged the sound >.< And I don't mean deleting it from within the game's save/load function, I mean like completely getting rid of it from your computer. The starting fresh to see if that makes any difference at all. Because back when I was testing other stuff during the jam, one of things I noticed was that once certain things bugged, they would unbug once save data had been registered, and it would impact the game from then on >.<
I can't say for sure, but whenever I download Unity games (same goes for the ones I've made) by default, the data seems to go under:
C:\Users\(your username)\AppData\LocalLow\MelancholyMarionette\LimboLine\NaninovelData\Saves
The appdata folder is hidden by default I think though, so you'd have to go into your folder and file settings and tick the box to enable hidden folders to show up. You can just delete the whole Limbo Line folder (both versions I guess if it generated a separate folder when you tried the potato version), and whenever you restart the game, it'll just generate a brand new folder.
But yeah, that's a real long shot, unfortunately >.< Sorry I can't be more helpful. This is one of the many reasons why I wish I was part of a permanent team.