What about inviting them in?

Their system leans heavily on being a pariah. A core tenet of the Juche philosophy is extreme self-reliance. Remember that Korea had been a puppet state of Imperial Japan, and they can see that even today the South has to permit a foreign military presence and kowtow to American political whims. They're willing to forego a lot to retain control over their fate.

Make them a part of the international community and provide a path where they can maintain sovereignity without keeping arms against the world, and it becomes harder to justify the hostility.

Yes, this means the current leaders endure and will get fat off of graft, but on a longer scale it promises boons for their people: development, integration, and a motive to de-escalate both because there's a gravy train to keep running and because there's less of a "you don't have to be as paranoid when everyone isn't out to get you" factor.

also. this is why my coworker recommended i stop using the names of these fuckfaces. every autocrat's name and face changes, but always they are the same people