A humble suggestion that when you release a nation why than it go to pre-set provinces as in all other paradox games what if a window akin to the EU peace window where you could choose what provinces of those with its cores in it or in the same state as those with those cores or maybe with all of your lands to choose from so that the new state can have the borders you want it to have without arsing around with selling provinces to it after the fact which deeply harms your prestige and doesnt make sense in story of the game terms.