For me, CK3 has been a far better introduction to the Crusader Kings series than CK2. It's a complex hybrid of grand strategy, RPG and simulator. Like Stellaris and the SIMs had a lovechild. It will only grow more complex with time, so I'd advise getting in early. For comparison I'm still utterly lost in CK2 due to 10 years of expansions and mechanics, yet I think I have a novice handle on CK3. Now excuse me, I need to get back to my bastard, witch, blood of the prophet, Assyrian Yezidi exile ruler who is conquering Siberia after being exiled by his people....