How to find lost Apple watch
How do i find my lost apple watch its is dead and not on find my
Apple Watch Series 1, watchOS 6
If the watch its dead, there is really not much else you can do to find it other than manually search for it. See the 'Put your Apple Watch in Lost Mode'and 'If you don't see your Apple Watch on the map' sections in:
If your Apple Watch is lost or stolen - Apple Support