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?
Not bad at all! You have your classic shuffle discovery, but also a playlist from songs you liked, and many exploration shortcuts like music by decades. It also got me into scrobbling to listenbrainz.