Cannot log into my paid subscription for Music

I lived in a different country when I got my first iPhone and when I moved back to the US, I could no longer use my log-in ID with Music because Music is, apparently owned by a subsidiary of Apple in each country.

So, Apple advised that I use a different ID for Music. So I did and things were just fine. I'd use ID_A for my phone account (addresses, backups, contacts, etc.) and ID_B for Music.

Move forward to today and I have my whole family on and iCloud+ account, and a Music+ account. And, everyone in my family can listen to anything they want on Music except me.

Since iosOS 18, I can no longer log into my Music account on my iPhone. Apparently they want to unify all the accounts. So, I've just been using my ID_B to log into the web app music.apple.com at work since I can't use my phone. When I attempted to do that today, it will not work.

I've already tried adding myself on IDB to my family. Apple disallows that.

I've also tied adding ID_B to my email addresses on my account ID_A. Apple disallows that.

How do I resolve this? I feel like the obvious choices are one of these:

1. Abandon my whole digital life on ID_A and disrupt years of backups for my whole family and switch everything to ID_B,
2. Disrupt my whole family as I quit my subscription for Music+ on ID_B and create a new one on ID_A, or
3. Apple abandons this "One Apple ID" thing
4. Apple changes my account on my Music+ account to ID_A.

Anyone have any other ideas?