By this method you will be able to put your watch into download mode and install firmwares by wires that you will need to solder inside your watch. In case your watch keeps rebooting over and over and then dies, or you can't connect over wifi/bluetooth connection or you had an update and crashed your watch, so here is the method used to fix that problem.
Finally samsung Gear S3 FRP got hacked. Looking all around the youtube and internet as of Date 11/06/2018 you can find no method for that, and there is way to reset FRP reactivation of Samsung Gear Watches. So after research on samsung gear s3 internal directories and finally the FRP got hacked. Below is the method used for this purpose. Hope it helps you sort out your Samsung watch, if not so you can contact for repairs.