Problem with Apple watch ultra
Cellular set up is blocked and have the message your account is not eligible to enable cellular on your apple watch. What is the problem with my watch please
That sounds like it's referring to your cellular account, not your Apple account.
Check with your cellular service provider.
M1 Mac mini, macOS 13.1; Watch, series 7 GPS/cellular, watchOS 9.2; iPad Pro 2nd Gen, iPadOS 16.2; iPhone 12 Pro, iOS 16.2; TV 4th Gen, tvOS 16.2; HomePods, audioOS 16.2 and Airport Express w/ Airplay 2