Given a clear and stark choice as to which is more valuable to the Red Chinese, rationality comes down on the side of simply calling Fatboi to China and offering him a deal he cannot refuse - on pain of a sudden “disappearance” or equally mysterious fate.
North Korea may be allowed to remain “Communist”, albeit in the Chinese version, anyway. But a regime “modification” may very well be in order.
There may be several North Korean generals who have the capability to present a more “moderate” face to the world than the Kim family. Communists should not have royalty anyway.
Communism has always been an aristocracy system that pretends it is not.