I have solved it in the following way: After passing the information from the 15 pro max to the 16 pro max, the phone stayed on the "Hello" screen and did not let you enter the password or advance from that screen. The phone got hot and ran out of battery.
I put the phone in DFU mode (quickly pressing volume up, volume down and the power button. When the screen remains with the apple, continue pressing power and volume down until the apple and the cable appear).
once a DFU, I connected it to my laptop (windows) to the iTunes application until it recognized the phone (VERY IMPORTANT, the cable has to be of quality, otherwise the laptop does not recognize it or the process goes wrong (I I had to use 3 cables until one worked for me)) When it recognizes it, it gives the option to restore it. Restore it with the IOS default version that iTunes provides.
When you see that it turns on and works normally, configure it as a new phone, download the most current version of IOS that you want (betas included) and now click restore the new iPhone. When you reboot, you can copy the old one to the new one and it won't stay dead again. Luck.