I cannot unpair my watch because it is not listed when I open the apple watch app.

To unpair and erase watch and remove Activation Lock.

On a computer, go to iCloud.com and sign in with your Apple ID.

Go to Find Iphone.

Select All Devices, then click your Apple Watch.

Click Erase Apple Watch.

Select Next until the device is erased.

Click the remove button next to your Apple Watch.