If KJU stays in power, they might go ahead with the Goryeo Union system proposed first by Kim Il-Sung.
Because SK does not recognize NK's official Korean name "Joseon" and NK does not recognize SK's official Korean name "Daehanminguk", Kim Il-Sung proposed forming of Goryeo Union in which SK and NK would be reunified under 1 country 2 systems principle like China and Hong Kong.
The official Korean name of this country would be Goryeo.
NK has always maintained this proposal for reunification since KIS first proposed it while the SK conservatives have always refused to recognize NK regime's legitimacy and seeked to absorb NK followed by sudden collapse of NK regime or getting rid of NK regime through a possible war in worse case scenario.
SK liberals, on the other hand, while disagreeing with NK's 1 country 2 systems proposal, agreed with forming the Goryeo Union.
SK liberal version of Goryeo Union wasn't 1 country 2 systems as proposed by NK, but a Korean version of European Union.
Under this version of Goryeo Union, SK and NK will remain 2 countries with their respective political systems, while forming a Korean version of European Union with 2 Korean member states.
The two states would then work together through Goryeo Union to form one country one day whether it takes 100 years, less, or more.
The past SK liberal presidencies agreed to forming such union with NK, which was pretty much scrapped off by the following conservative presidents.
Now that current SK president is once again a liberal, however, it looks like they are gonna go ahead with the Goryeo Union plan if the talk between Trump and Kim go well. Forming such union has always been one of election pledges of Moon, the current president, since he first ran for president in 2012.
Here's my guess on how this Goryeo Union is going to be like.
Just as EU designated Brussels as the capital city of EU, the capital of Goryeo Union would be Kaesong, the capital city of Goryeo dynasty.
Seoul would be referred to as Namgyeong(the southern capital) and Pyongyang would be referred to as Seogyeong(the western capital) as they were called back in Goryeo dynasty.
Sad if this happens because I don't want KJU staying in power. If this was to happen, KJU should at least open NK up, institute Chinese style capitalism, and legalize Kpop & SK dramas&films, because it just doesn't make any sense to form an union with such a closed authoritarian society like NK. I highly doubt KJU would do that though, because opening up their country to the free world means end of KJU's regime.