Mailbox.org is also a good option AFAIK.

Old School Runescape if you like grinding. But you might never quit if you get hooked :')

I have been very happy with desec.io, they are a nonprofit based in Berlin.

This anecdote brings me a lot of joy for some reason haha.

Thank you everyone for the helpful replies!

Nextcloud + Nextcloud Music App is also a good solution. The app supports subsonic too, so it can be used with a few different apps.

Very excited to try this out. Already have 70 hours on my deck. Supergiant Games is awesome!