EU4 > HOI4 > CK3 > Stellaris, imo.
The most frustrating thing with Crusader Kings for me is the early-game partition laws. I don't want to have to repeatedly reconquer my land when my character die's every time. I'd rather take-over the world for the red banner of Syndicalism in Kaissereich or rebuild Prussia in EU4.
I imagine this would be pretty easy with that Viking guy who gets like 10k armies at start though?
There’s a mod so you can adopt primogeniture right at the start. It’s kind of a cheat but sure is less frustrating with it.