You’ll need that Apple ID and password, or will need to contact Apple to sort this out, as you will not be able to bypass Activation Lock here.
You’ll need to provide the purchase receipt with the Watch serial number as part of this, if no Apple ID…
Nobody here can help you bypass Activation Lock and—absent receipts or other acceptable proof of ownership—Apple won’t.
Info on recovering access to that previous Apple ID, or contacting Apple:
If you forgot your Apple ID password - Apple Support
If you forgot your Apple ID - Apple Support
How to use account recovery when you can’t reset your Apple ID password - Apple Support
Contact Apple for help with Apple ID account security - Apple Support