Hey there!
Hmm, the discord link is now a permanent invite link that supposedly always works indeed! If you'd like, you could send me your Discord username in private and I can maybe check, but I have no idea why it wouldn't work!
As for the OST, unfortunately, we don't have that available anywhere yet as we're still working on improving the game's music more and more! Eventually though, I'd love to have it available! I'll make sure to announce it everywhere, Itch included, when that happens!
Thank you for your kind words! :D I hope you'll keep enjoying the next updates as well!