Remove activation lock on my Apple Watch

Only the previous owner can remove the Activation Lock, if you do not know the Apple Account and Apple Account password that has been used to set up the watch:

About Activation Lock on your Apple Watch - Apple Support

The official Apple Support might be able to help, if you have proof of ownership, as explained in this article:

Additional Support - Activation Lock

the person it's locked to needs to take the following steps

What to do before you sell, give away, or trade in your Apple Watch, or buy one from someone else - Apple Support