Hi disconnected my apple eight series ultra watch from the phone. It was linked to an upgraded that phone to watch now says it is ready to pair to the new phone and when I go to pair it, it says that I must enter the old Apple ID I be

Why would you create a new Apple ID? That is a bad idea!

All of the content; apps, music, games, etc that you acquired, both paid and free, are permanently tied to that Apple ID. You won't be able to update or redownload anything with the new Apple ID. To do so would require you to delete everything and acquire it all again with the new Apple ID, including buying all the paid content again.

Your Watch Ultra is currently under Activation Lock to your original Apple ID.

You can remove the Activation Lock, but a new Apple ID is a bad idea.

Activation Lock removal -

How to remove Activation Lock - Apple Support

M1 Mac mini, macOS 13.4;  Watch, series 7 GPS/cellular, watchOS 9.5; iPad Pro 2nd Gen, iPadOS 16.5; iPhone 12 Pro, iOS 16.5; TV 4th Gen, tvOS 16.5; HomePods, audioOS 16.5 and Airport Express w/ Airplay 2