They had a lot more social features on Spotify back in the early days. You could chat, share songs/curate playlists together, listen to the same playlist and change the song for everyone, etc. But I think they took a lot of that stuff out. At least they did for a while because the removal of that stuff is why I stopped using Spotify like 12 years ago.

I was that kid running my own proxy server at home. I charged $5 for access but people just started sharing credentials instead of paying lol

Animated JXL worked for me on Firefox mobile after enabling that flag in about:config