Fantastic idea and implementation! Just FYI, it seems that in the music community, there are quite some complaints about how Spotify distributes the income for artists. I don't know the details so no further comments from me. But I think it would be great if this project can be abstracted into an indie Web Audio visualisation lib. I would be keen to try it with my project Glicol:

https://glicol.org

There I have only basic visualisation so far.