This device cannot be transferred

I get this message when trying to download music on my new iPhone 16 Pro:

"This device cannot be transferred"

And after that some nonsense text which says I have to wait a certain number of days. From looking into other posts, I can see that this is a well known problem since at least 5 years. The Device was transferred to me from another Family Member. We followed every step needed to transfer a device.

After reviewing a lot of community post on this and trying everything out, I still could not find any solution to this. So I am now paying the full price for Apple Music without having a key feature, which is downloading music.

I live in Germany. I'm not sure what the state is in the US, but I am very confident that something like this is illegal.

I don't Understand why there is no fix to this. Every other iCloud service works just fine on my iPhone. What are you guys doing at Apple Music?