You can use ListenBrainz to discover new music based on your listening activity from your self-hosted library. I've started doing this recently with Navidrome and I'm happy with the results. This is the plugin I've been using: https://github.com/kgarner7/navidrome-listenbrainz-daily-pla....

There is also Troi[1], a tool provided by ListenBrainz to generate playlists and radios from your local music collection.

[1] https://troi.readthedocs.io/en/latest/index.html