The OnePlus Watch is available for free with the purchase of a new 10 Pro Android flagship smartphone. However, this offer is a flash sale in effect for one day (May 11, 2022) only, and seems to be valid in the US and Canada only. Then again, it might prove a good enough deal for those who can get it.
https://www.notebookcheck.net/OnePlus-10-Pro-is-offered-with-a-free-Watch-in-a-May-11-2022-only-event.619074.0.html