As for new things, I stumble upon them.

Sometimes (rarely) I swap to (digital) radio, and occasionally hear songs I'm interested there. From song, I often check out the artist's other songs too.

Sometimes (maybe always if they show up for me?) I check out songs or genres when they come up here on Lemmy. Not that it's been particularly successful in giving me new favorites or likes.

I find Arte Tracks quite interesting and it makes me look up genres and music. Not that it's been particularly successful in giving me new favorites.

Tracks reports on geek culture, current music, film and emerging artistic forms

YouTube Music algorithm streaming me new songs. When they stand out to me I give them a like, playlist them, and/or check out the artist. Soundcloud also has back-filling streaming modes and related songs.

Sometimes in videos (including online, series, anime here) I hear music that stands out to me and I look up.

As for switching up the kind of genre or platform, it's by mood or chance.