Well, I previously encountered this problem on iOS 15.4 something, but I’m not sure I can downgrade. iOS 15.8 is the latest offered for my hardware, so I can’t go up either.
Other than that, the only iOS devices i have on my apple membership are iPhones, but you don’t offer playbeat on that.
So short answer, no, I don’t see any options for trying this out on other hardware.
If you really think this is a quirk of my hardware, and it can’t be fixed or even replicated, I think what will make most sense is to take your earlier suggestion and ask apple for a refund for this app, until such time as I choose to update my (otherwise adequate) hardware.
However if you think you have a shot at reproducing this problem on a mini4, I will hold fire on that for a bit. I would like this to work.