Thank you. Do you know the reason why Apple requires WiFi by any chance?
I was finally able to speak with a very knowledgeable tech agent at Apple who gave me the same answer as you This was after I had been told repeatedly by others that it was absolutely possible simply because "an iPhone recognizes a personal hotspot as non different from WiFi".
Obviously, if you try to do an iCloud backup or an iOS update using a personal hotspot, you won’t be successful. I still don’t understand why WiFi is required though. I’m sure that I’m not the only person without access to WiFi but with access to a very strong, secure and stable cellular connection. Now, with the addition of 5G connectivity.., won’t cellular connectivity improve even more significantly?