Any add-on device will likely look like an afterthought. If it were me, as suggested I'd install a new switch somewhere. I'd pull the switch out of the wall and disconnect the wires. Then extend wires up the wall to a new switch location - that is, assuming you can get wires to the a new location. If the wall is an interior wall, it will be hollow and easy to get wires into. If on the end of a cabinet, you can tuck the wires in a corner of the cabinet where you won't see it. You can always reconnect the switch in the future if desired.
Maybe you could wire the old switch to a loud buzzer, that way switches will probably never get touched again, lol.