Can’t find either devices on each other to unpair

I just want to make sure that you are checking in the right direction and may therefore end up recommending what you may have already checked. Open the Watch App ➔ All Watches (Top Left) : Here, you will see your Apple Watch ➔ Tap on the "i" to the right ➔ Unpair Apple Watch.

Axel F.

In your list of device under BLUETOOTH in settings, does your iPhone show the Apple Watch and does it show that it is connected to it? If YES then shut down and restart the iPhone and the Apple watch. Shutdown and restart the iPhone first and then the Apple Watch. Does that resolve the issue? If NOT then can you give us some details on the history of the Apple Watch? Was the Apple Watch purchased and paired successfully with the current iPhone etc.? Thanks.

Axel F.