this is stupid. if a killswitch solution was feasible it was already implemented in notebooks many years ago. all the previous attempts failed. If you invent a killswitch method it is certain that hackers will find a workaround.
also there's already a killswitch method used by carriers. it blocks the imei and it can't be used on nationwide networks. but even this method can be worthless if someone changes (illegally) but easily the smarthpone imei.
also even if it was technologically possible (it isn't) the thefts would still continue because parts can be used. only the soc would be unusable. but all the modules would work flawless like, screen, digitalizer, case, battery, shell, camera, antennas, memory card etc.
so good luck with that but it won't work.