How to remove Activation lock on Apple Watch?

Then you'll need to contact Apple Support as explained in the support document linked below to have them release it.

You will need to provide proof of purchase from Apple or an authorized Apple Reseller in the form of a receipt or invoice.

click here ➜ How to remove Activation Lock - Apple Support

What is the issue exactly?

Is the Apple ID locked?

Or is the Apple Watch locked to an Apple ID to you don't know or don't have the password for?

click here ➜ Writing an effective Apple Support Communities Question - Apple Community

then maybe here ➜ If your Apple Account is locked, not active, or disabled - Apple Support

or here ➜ About Activation Lock on your Apple Watch - Apple Support