I just completed the big project of overhauling my whole Spotify *from scratch* which involved a lot of work but I'm really happy with how it's turned out.
The issue with my old system was I had a ton of abandoned playlists that didn't function so never got played so I started to just 'like' everything I was listening to with the hopes of just clicking shuffle and hoping for the best which often ended up annoying me because there was 0 cohesion.
Now I have playlists set up according to genre and also playlists based on vibes. I even set up an 'everything' playlist which has, well, everything lol (I listen to a lot of music so I like to be able to search particular artists/song titles with ease to find what version I have saved)
I even have a 'not anymore' playlist so that I can hoard the stuff I don't like anymore and don't care to have pop up on a shuffle play.
If you read this far, I'd be interested to hear how you categorise your music