I've tried all streaming platforms on and off over the years. I've always returned to DRM-free methods (if you know what I mean). I currently self-host Navidrome. Not the best for discovery though, for that, maybe try InnerTune.

This might sound stupid but CDs. I buy CDs and rip them to FLAC to listen with Strawberry Music Player or Jellyfin.

If I were to ditch Spotify, I guess I would go back to mp3s.

Bandcamp isn't open source but pretty fair IMO and you can stream via Newpipe or Kodi plugin. It is not a direct alternative but good enough. Using Newpipe you can also access everything on Youtube Music.

An option is FunkWhale, but most instances don't allow copyrighted music so most (if not a lot) of famous and music artists in general aren't available there

unless, of course, you host your own instance, since it's self-hostable and decentralized too

In an ideal world I'd continue to use my self hosted Navidrome setup but acquiring new music and keeping my library organised is time consuming regardless if how much amazing automated software is out there.

I mostly stick to Innertune at the moment and will probably be fully converted once they add support for YouTube Music login.