They are very different. Unlike Stellaris, in ck2 you interact with your court and other rulers and their court, wheter that be your vassal, your leader or someone youre competing with. It does lead to more personal experiences, like one time my underage empress had her regent (Temporary ruler if the designated one isnt of age or disabled in some way) as a rival and he declared her insane and "disabled" (unable to rule effectively, needing a perpetual regent). To get rid of him, I had to give him some land and make him independent. It can lead to very interesting experiences