F-Droid

Auxio seems to be most simple and reliable, but I really adore the ui of Gramophone

https://apt.izzysoft.de/fdroid/index/apk/org.akanework.gramophone

It's not perfect though, they're still working on it. For some reason the meta data for album art for some or the albums/tracks in my library doesn't get picked up properly, I need to open open a bug report about it. But that issue is present in many players I tried, so I'm not sure if there's a shared library they use that doesn't like the way I've tagged those files, or if I just did something wrong in tagging them.

And playlist support is currently not finished- I have a small library so thats fine with me.

Auxio, my old iPod, and the music tagging tool I grabbed off fdroid, all handled those files with no issues though, so auxio seems like a great tried and true, simple pick :)

I vaguely recall metro and retro being fairly good experiences when I used them, but it was a ways back and I wasn't listening to local files as much. I believe metro is a fork, most people here prefer that one so I'd go with it if retro is even still around

Edit: yeah metro even let's you edit meta data from within the app, doesn't see album art for a given song, I hit edit to add the album art and the editor already sees the album art for it no problem despite the player having no art for it, I replace the album art with a newly downloaded file and hit save, the album art is still not recognized lol

If anyone has suggestions I'd be happy to hear them, I'm newer to keeping a local music library