I was also experimenting with finding a popularity score for songs and artists. The last.fm API worked well for this, but then that was just using an API, so there was a lot of other sources that I was looking into, like using pageviews on the Wikipedia article for an artist.
I've thought about making a new open source version at some point if I get time. I think I've got a decent idea how to make something work quite well now, basically make a vector with the genres/styles, do dimensionality reduction and then store in vector database, so you get like an embedding of the album essentially. A bit like those language models embed words in a vector space, but you don't need a neural network to do it, since that job is done already by humans who have listened to the music and tagged it.
