easier and better that China attempt to "fix" North Korea than the US.

Our most recent Defense Strategic Guidance says in effect, "no more massive, expensive COIN/nation building efforts like we just stumbled through in Iraq and Afghanistan" (paraphrase).

Any effort to go into a post-conflict DPRK and "fix" them would would likely trigger a far worse resistance insurgencies than we created and then attempted to resolve in those two afore mentioned locations. Far better we let China own that mission. I think we can live with China having greater influence in the DPRK than we can with what it would cost for us to attempt to force an American solution.