Spotify's shuffle tends to always pay the same stuff because Spotify is a scumbag company that nobody should use. Spotify prioritizes the tracks that cost them the least in royalties per stream. So, it's not that their shuffle algorithm is bad. It's that their shuffle algorithm is INTENTIONALLY bad to fuck over artist.
The bad user experience you get as a result is just collateral damage and they really couldn't give a fuck about that.
When I would listen to an opera, which I wanted to listen to the whole recording and not shuffle anything, Spotify thought I needed a little Britney Spears in the middle of Una Furtiva Lagrima, which was just sacrilege. I was only in there a minute, I quit Spotify because of Joe Rogan and the antivaxxers shit, and how they've ruined the best podcasts that existed. I hate streaming music,I think I'll try Deezer and see if I like it better than YouTube Music, which sucks a lot too.