Apple Watch: This does NOT seamlessly transfer over (well, not for me it didn’t). As the watch was already paired to the iPhone 12, it first needed to manually be unpaired before the pop up shows on the new phone to transfer the watch across (all my ring activities carried across - someone was saying they had issues with this).
I still have to setup my new phone too. Was hoping my watch would transfer over seamlessly as I have seen others mention on here. I wonder why some people seem to get a prompt to move the watch, others need to manually unpair and re-pair. When I last changed my phone (iPhone X to iPhone 11 Pro Max) I has to manually move the watch too.