CK3 vs EU4 which one?

[Herman Gigglethorpe]

Recently started getting into CK2, and what really helped me were searching up a beginner's guide on Youtube, and playing as an Irish ruler in the 1066 start. You start tiny, meaning that you don't get overwhelmed with complexity. Your with neighbors that are usually of equal power or weaker than you. The big powers (mostly England) usually leave you alone. There's an obvious initial goal: unify Ireland, and achieving it will give the basics of warfare. And later down the line, the special Tanistry succession means it's pretty simple to keep your realm in one piece, instead of it all splintering upon your ruler's death. All in all, it's a safe, forgiving situation.

This is good advice.  I played as Ireland when the game would (barely) run on my computer, and it was a good tutorial location.  Crusader Kings 2 is more intuitive than you might expect.  Unless the AI has changed since then, beware of Scotland, not England!  England tended to break apart in my playthrough, but Scotland always had the chance to invade.  Don't know what Tanistry is since it must have come in a later expansion.  When I played the Irish rulers had the generic feudal titles like Duke.

[Amicalola]

That is also how I learned CK2, it's good advice. You're right that the in-game tutorial is a shambles at best, even when it came out, let alone with expansions. Watching a youtube tutorial is another good option, combining that with an Ireland playthrough (or three) should have you ready to go. But yeah, I sympathise on the game being hard to get into initially.