Tailscale is pretty good, and i generally like the company, but there are definitely some gaps. For awhile it even lacked proper ipv6 support with mullvad.

There isn’t a reason you can’t use those same services for downloading any content you want. If you are using a front end of some kind, you can just try sourcing the content yourself and using a music streaming app. It’s been awhile since I’ve looked into it, but there was subsonic. Also, most of the video servers like emby and plex also support music.