My new iPhone 13 is stuck at 200MB restoring from the back up of my old phone.

I set my new iPhone 13 to restore from the backup of my old iPhone 6S. I've had it for nearly two weeks, and it's been stuck at the last 200MB since the first day. Now I can't upgrade to iOS 15.3 until it finishes.

It occasionally asks if I want to use WiFi to restore but never when I'm at home or at work when I have access to a WiFI network. So I have to tap later.

I tried to use the stop restore option, but when I tap on that nothing happens.

Please advise.

Thanks!