Symphonium supports playlists. You can make a own manual playlist or a “smart” playlist, which has the x amount of least listened to songs, the 10 highest rated ones and so on. Everything is on the listening device local, so you have to backup for yourself. Symphonium is really really customizable.

Sorry for german. A setting for an intelligent playlist for all highly rated songs which I havent listented to in 70 days. (AND/OR) can be set for rules. Its amazing.

Music recommendation is not really a thing unfortunately by the nature which most of download->server->jellyfin->client systems run.

You really need the “big data”-aspect which spotify or similar providers have to have good recommendation, so no local solution is possible. I sometimes use listenbrainz (by the musicbrainz team) like lastfm and then manually aquire new music I want to have on my musicserver.

Jellyfin works nicely for music, as long as you use a good client. The native jellyfin mobile app is not optimized for music. I use symphonium for android listening and am very pleased with it. More settings than Id ever need, different options for downloading/caching songs on device, support for subtitles and all.