Lost watch

I lost my apple watch yesterday at the river around 4p while in a “no cellular service” area. I immediately marked it as lost in the “find my” app but was unable to locate because of no service. In the “find my” app, the last location was shown as a store I stopped at before the river all of yesterday afternoon even after returning to service area and getting home and connecting to Wi-Fi. . At 1:32a last night, the location updated to my house and I can now play the sound to locate it, but I haven’t been able to find it today. Since the location address updated, does this mean I didn’t leave my watch and it’s possibly at my house in my vehicle or one of my bags? How accurate is this? And would it play the sound if my watch was dead?