The domain limit is a mechanic that tries to discourage this, as it severely penalises you for going over the limit.
So what is ‘North Korea’? Basically, you ignore the existence of vassals, titles, and everything the game wants you to care about, instead directly holding everything yourself. There are a few steps you’ll have to take to pull off this strategy, and full credit to YouTube channel Reman’s Paradox for an excellent video run-through of how it all works.
How to do the North Korea strategy in CK3
