Yeah, I was afraid of that.
This is a known problem with Jasco in wall switches. Nothing to do with SmartThings–you’ll find the same problem discussed on Vera and Homeseer boards.
The good news is you don’t usually have to do all the work you’ve been doing. Instead, cut power at the breaker, restore power, and you may find the switch is found again.
If not, still cut and restore power, exclude the switch, then do a zwave “replace” as though it were a new device, and at least you won’t have to touch the Smartapps.
https://support.smartthings.com/hc/en-us/articles/204392810-Z-Wave-Replace-Failed-Device