What to do when Apple Watch Series 5 is iCloud Locked?

Any specific questions about Activation Lock?

Activation Lock is intended as a theft deterrent mechanism, and is intentionally difficult to bypass.

Recover access to your Apple ID if this lock is held by one your Apple IDs or present original proof of purchase receipts or other similarly convincing ownership detaile to Apple, or contact the seller and request they remove the lock or request a refund if this Watch was more recently acquired.

If the seller has disappeared and as is too often the case, this Watch will never be useful, and you’ll want to recycle it.

This is written for iPad and iPhone, bur also applies to Watch: https://discussions.apple.com/docs/DOC-250001038