Paradox games have a bad habit of being overwhelmed by the cruft of their expansions, and CK2 was no exception. The game is phenomenal, but there are so many different unrelated systems (and systems in the vanilla game to support the DLC) that it can be incomprehensible.
CK3 so far has taken the best insights of those expansions (dynasty/bloodline maintenance, personal armies, skill specialization) and integrated them into the main game. The DLC has been a coin toss whether it is so well-tied-in (I think the culture-molding mechanic is less awkward than the throne room and artifacts or the iberian politics that somehow everyone on earth is privy to).
CK3 so far has taken the best insights of those expansions (dynasty/bloodline maintenance, personal armies, skill specialization) and integrated them into the main game. The DLC has been a coin toss whether it is so well-tied-in (I think the culture-molding mechanic is less awkward than the throne room and artifacts or the iberian politics that somehow everyone on earth is privy to).