This has just worked for me and my Apple Watch series 3.
Updated the software using a old iPhone 6 watch app that had not been updated I think it had iOS 7 .Then turned that phone off.I then paired as normal with my iPhone 8 iOS 14 watch app and it worked I don’t know how or why but I’m happy.Good luck
Kari88
Users receive reputation points by contributing quality content to the forums.
Posts include post and replies published on the forums.
Post authors can mark replies as Accepted to indicate successful solutions.
Apple Developer Forums admins can mark replies as Apple Recommended to indicate an approved solution
Last seen
From
England