General use: Musicolet (free, no ads)

If I want to change the pitch and speed of the music: Music Speed Changer (free with ads, removable with a 1 time purchase)

Try Retro Music Player. It’s a beautiful app + it’s open source.

I’ve been using vanilla music. There is a plugin for it that lets you find metadata (album name, artist, album cover etc.) for songs automatically.

Neutron player + DAC is the way to go