Success!! (Without needing to Reset the watch)
This is how I did it on two different, new iPhones and older SE watches.
- Of course activate the new phone and transfer data/settings from the old phone :)
- Power off the old phone
- Plug the new iPhone and SE watch into its power source (this is the important step)
(Keep the devices close to each ther for the rest of the steps)
- Restart the new iphone 15 and the SE watch
- Open Watch app on new iPhone and select pair to existing watch
- Follow the prompted instructions to pair the devices
- Let the Watch do it's thing by slowly going around clockwise, do not interrupt this process
(time to pair and copy data diffes depending on how much you have stored in Fitness and Health...)
That's it!! Hope it works for you also :)