[Semaphor]

Symfonium [0] (which supports pretty much anything but koel) is a commercial android app, can cache & export, have rules for doing so automatically, supports a rolling cache, can decide via wifi connection if the cached or online version should be used. You can also choose if you want original files or transcoded ones.

[0]: https://symfonium.app/

[gerjomarty]

Thank you so much! Will be very happy to move to something that isn't YouTube Music.

[tonyedwardspz]

+1 for Symphonium. It's a great app that makes self hosted music not feel sucky. I live offline first and can attestb to it's caching capabilities.