Howdy. Just chiming in as a happy Jellyfin user. I'm running multiple instances since my music library was significantly affecting my primary video instance, to the point of not letting Android TV clients load the home page properly.

I've since split out the music and am a happy camper. I briefly tried out Navidrome for music but wasn't happy without the ability to edit metadata from the UI (even if the Jellyfin metadata editing doesn't affect ID3 tags anyway). It may not be be FOSS, but Symfoniun is a fantastic Android music app that supports Jellyfin and DLNA casting.