I have experimented with FinAmp, Jellyfin, Plexamp, and Symformium.
I really hate to say it, but Plexamp is the best out of all of them. The thing is, I wanted to ditch Plex because I do not like them anymore.
Can anyone recommend me a good free app for Android that can stream my music collection?
Airsonic or Navidrome server, plus one of the various Subsonic apps. I like Substreamer or Dsub but there are plenty of other options.