Through my Apple Music “New Music” weekly playlist before I canceled my subscription. It does a good job so long as you actively love and dislike tracks.
Now I have a local library that syncs with last.fm for every play and you can discover new music and artists through there.
I’m no longer on it but instagram was actually a great way to discover new artists. Seems that meta will be a significant player in the music industry (major UMG deal) soon as well so who knows what’s coming there.