Think about it, South Korea is a pretty technologically advanced place, they could make their own switchblade equivalents, customized for their specific needs. North Korea has an estimated 50,000 artillery pieces arrayed at the South Korean capitol just to the north over the DMZ, which, ironically is practically tiled with mines. Now imagine 100,000 computer controlled switchblades taking out every one of those artillery pieces and many crews along with ammo dumps, they know where every one is. Next if they know where he keeps his nukes, stealth starlink drones could take care of them, guided automatically by GPS only transmitting when they reach the target. Next on the hit list for stealth drone strikes would be the fat little fuck and his top people, all done simultaneously late at night while they are in bed. I might cost a billion, but it gives them first strike, neutralizes his artillery and nukes and decapitates the leadership in a single simultaneous stroke. Other drones can hit communications and AA defense points and others can destroy planes on the ground and their command and control. Much done at the push of a button when the highly secret system is in place. They can also use precision rockets on the artillery and nukes, just to make sure, after the initial strike.
This is what modern technology can do to an old fashioned soviet style army like NK with demoralized conscript troops that they dare not trust. Deal with the nukes and artillery arrayed at the capitol and the SK army could go through them like shit through a goose and be at the Yalu river across from China in a day or two at most. I don't think the population would be hostile either, food distribution along the way would take care of that. If Americans weren't involved, or were no longer there, the Chinese might buy into it, or not want to fuck with SK after they did that!