Mine transferred ~660 gb from my 15 Pro to my 16 Pro in about 45 minutes, total time about 75 minutes after re-entering security info for cards in wallet and waiting for various apps to download. Both phones were plugged into power. Both running iOS18.
I wonder if transfer from older devices accounts for some of these accounts of excessive time required for phone to phone setups.
As usual, the only thing that didn’t transfer were Bluetooth settings for non Apple devices. I did have to go into settings to change the device name, as the old name copied over as well, which is also normal.
I set battery max charge to 95%- this morning pulled off the charger at 5:30 AM and was astounded to find it still at 90% at 11 AM despite continuing background optimization going on.