You do it in slow, intelligently-developed stages.
first stage is simply ceremonial.
then over the course of... literally decades...you slowly reunite. shyt won’t be done overnight. Perhaps one leg of the unification could involve using labor in the north to manufacture goods designed in the south (instead of using China).
I’m not gonna pretend like I know all the answers and have some drawn out plan, but I do think, long term, it’s feasible to reunite and be economically prosperous.
Among societal, economic and military instability you really doubt the northerners won't flee to China or the south by the millions?
The populace of North Korea is heavily indoctrinated can you imagine how much it would cost to remove that brainwashing if at all possible?
An ungodly amount.
Then there's the rampant discrimination against the escapees. Southerners and northerners wonThe sheer education disparancies, which would cost several billion to start up on a yearly basis. Even if they only concentrate on children that are still developing that's increasing their education budget by 100% if they wanna do it right.
Then the fact there is little to no industry, their farming industry is a shyt show. Literally. Go look up the meaning of
nightsoil.
At best they would stagnate, most probably they would face an economic collapse. Even in the best case scenario they would be below China, Japan, Vietnam, Indonesia as Asian influencers.
Although, if 40-70 years down the line these among many, many other issues are stamped out, there is a succession of competent governance they could plausibly become a top 5 nation. Well beyond Germany or Japan. But again, too much uncertainty to even call this a "boom or bust" situation.