How can I locate a lost Apple Watch using Find My and Bluetooth signals?

Hello Apple community

So on monday I noticed my wath was missing. I put it on in the morning and noticed it was missing on my way back from the waste management facility.

Here is the story.

I loaded up a large trailer with grass clippings and palm branches (hand loaded throwing the grass into the trailer.

I then took this to the waste management and unloaded it by tipping out the trailer.

On my way back I checked the time and my watch was missing.

To answer your questions

I didn't notice the watch was missing until after and I can't be sure I had it on when I left the house.

Ok so I activated find my and it said that the watch was still in my house. When I tried the loaction directions part of the app it would only show up as a map (not the fancy circle with the distances on it). It was a series 3 watch so may not have these things.

Then I turned on bluetooth and it connected to the watch outside of the house (but dropped out when I was in the house). I went to the area where I loaded the trailer and the signal dropped out.

Based on htis connection I narrowed down the search area into an approximately 100 sq m area. This is all well mown (recently) and we searched without success.

I went back to the waste management facility and trie the "find my" and bluetooth and it did ot connect there. I was standing exactly where the dumped pile of grass clippings were and moved the grass. No bluetooth signal was detected.

When I returned home it once again connected to my phone in the same area. I activated the cellular component and we tried calling the phone and it did not ring. We even tried at night to see if it would light up.

The following day I returned to the waste management and three of us searched the grass clippings without success. By this time the watch was now flat and not connecting to bluetooth.

So my questions are

If it only connected to bluetooth at my house is that a 100% proof that the watch is here?

Is there any other explanation.

If I know it is here I will borrow a metal detector.

Yes I know it is a series 3 watch however it was mine and it has sentimental value.

Any assistance appreciated.

[Re-Titled by Moderator]