Re: I now have an identical model as backup!
All the 2FA that I'm forced to use, uses SMS. Those can be diverted or intercepted.
But it's the PHONE NUMBER you need, not an identical phone. I've tested by putting the SIM in a basic GSM only 2.5" square screen feature phone. Still works.
So how do I clone my SIM for my backup phone (a nice 4.3" Sony Android)? You can get a new free SIM from an operator. Getting the same number from a lost or stolen SIM is hard. In contrast, changing operator and having existing number from a not-lost SIM transferred works in less than 15 minutes.
I view Apple's software SIM idea as simply Apple's way to lock you to an iPhone.