Thanks ! Unfortunately I didn’t find a “free/open license” soundtrack that matched well with this game. (Don’t mind the two deleted comment itch io kinda bugged on me.)
Viewing post in The library of the evil book jam comments
Have look at these, maybe there's something you would find fitting:
https://incompetech.filmmusic.io/topics/horror
They're mostly (maybe all) licensed under Creative Commons with Attribution. So you can use them for free if you credit the author.