how can I find an Apple Watch that wasn't set up? I lost it
lost Apple Watch
Question marked as
You can’t. You get to look for it “the old fashioned way”.
For a cellular Watch, you can report the IMEI to your carrier and they can ban it, but Apple provides no means to locate by IMEI or by serial number.
Since it was not set up, most (all?) if this does not apply: If your device is lost or stolen - Apple Support