"Show Apple Music" option missing

Hi, a couple of months ago, I moved from an iPhone 8 to an iPhone 11. As part of that process I also moved from iOS 14 to iOS 15. I did this via a backup/restore process via iTunes on my PC. After doing this, I can no longer access my Apple Music subscription, the only music appearing on my phone is downloaded songs and playlists.

All of the online troubleshooting starts with turning the "show apple music" on/off etc but I don't even have that option. I know where it should be but the option is not available at all. My Apple Music subscription is still active (it's via Home Sharing) and other family members are still using their subscription fine too. Under my Apple ID settings on the phone, under Family Sharing I can see my own name, and Apple Music is listed under "shared with you and your family".

I've logged out of my apple ID on the phone, and logged back in, I've restarted the phone, I've toggled the "sync library" option on/off, nothing changes.

I cannot find any additional information on these Apple forums, other than similar sounding issues with no apparent solution.

I'd really appreciate it if someone could assist me / suggest anything.

Dan