You mean this one?
Yeah, it was about time the developers make an in-depth tutorial for the game, the in-game tutorial doesn't even scratch the surface and as you have pointed out, the game has become more and more complicated with each new DLC, adding more game mechanics that you have to know about and keep in check. You need to know a lot of theory to play Hearts of Iron 4 on a decent level in multiplayer, there are so many things to look after that calling the game non-intuitive is an understatement, it's easy to forget about something and have the game ruined because of it, best to have each of them explained in a practical and fun manner.
Personally, I learned from this video:
But it is outdated and it doesn't explain you what's the best thing to do for each game mechanic, it simply lists you what they are and how they work. It's good if you only want to learn how the game works in 40 minutes, but it's not good if you want to learn how to best play the game which is where the absolute beginner tutorial comes in.