I bought a new M5 iPadPro. I previously used an iPadPro from 2019, which was an Intel device if that makes any difference. Going through the setup procedure for the new iPad, you are given an option to Set Up from your old iPad. I took that choice.
That became an 8-hour nightmare. I simply could not get through the setup procedure. The biggest hurdle revolved around verifying my Apple ID. A code would allegedly be sent to my iPhone. But I would see only a ¼ sec flash of the confirmation window on the phone. I never got a code. That led to three sessions with Apple support, ultimately escalated to a senior support person.
The fundamental problem (which led to other problems, which in turn took a lot of resetting to fix) was that I was running an iOS 26 beta on my old iPad. That interfered with proper pairing with the new iPad. I had turned off beta updates on the old iPad and had turned on “Automatic Updates”. I had not paid too much attention to the matter, but in my mind, I had come to believe that I was running the regular version of iOS 26, but in fact, it was still a beta and had not been replaced yet.
I write this just as a warning to someone who might follow my path. Make sure that you are not running a beta version of iPad OS 26 on your old setup iPad. In the middle of all this, I was so angry that I planned to return the new iPad… The delta between the “fun” of getting a new, fast, beautiful iPad & getting a chance to play with it versus staying up until 4:00 AM talking to Apple Support Chat was huge.