I’m running dev beta one on my iPhone right now and I am a bit shocked at how well it’s running. Usually the first dev beta is borderline unusable, but this runs better than iOS 26 on my phone.
Regarding the same number on multiple phones, that is something we have been doing for decades. In the 90s, it was usually a carphone and a mobile phone, then later a phone and PC, but my ex-boss, for example, had an iPhone 5 permanently attached to his BMW and a 5S as his normal phone, so he didn’t need to have to mess around with cables, when he got in the car, he just got in and drove and the phone in the car was always ready to go.
These days, with wireless CarPlay, I suspect he just uses one phone.