This might not be what you're looking for, but I get a lot of my new music from listening to the radio and talking to friends about music. Also, browsing Bandcamp of bands I like and seeing what they like goes a long way.
Piracy
Welcome to /c/piracy
No netflix or streaming services landlubbers allowed, this is pirates territory.
Services like Last.FM and ListenBrainz will eventually give good recommendations. They need LOTS of listens to figure it out. Last.FM, before I stopped using it, was very accurate.
Now I just keep track of releases on Bandcamp, Resident Advisor, AOTY, etc. via RSS feeds.
What style of music do you listen to?
Last.fm works pretty well, but my main issue with it, is that it is proprietary, so I would like to avoid it if possible. I tried using ListenBrainz but even after few weeks of my data it doesn't give me any recommendations and even when looking at users that are considered similar they are listening to completely different things.
Not really sure what is the style. Mainly just OSTs from anime, games etc. Take a look.
Yes, ListenBrainz takes AGES to figure out recommendations. I have scrobbles going back to 2006 and even when I imported them it still took weeks to suggest something. I too left Last.FM due to the proprietary nature. You might have to find a niche blog or something if you want to find more music.
Vimusic is an open source youtube music client for android which has a radio feature + the ability to create playlists and follow artists. Great to disciver new songs.
If that doesn't suit you there is Recommelody, a flutter app that recommends music based on user favourites, using the Spotify Web API.
Thanks for suggestions, but those don't really help me if I want to use a self-hosted solution. I would have to either go back to YouTube or use Spotify.
Seconding ViMusic and adding using SpotX or XManager to use Spotify's service to discover stuff for you without having to pay.