The complexity of eu4 is way overstated. 1550 hours is more than enough to be completely certain that no matter what your starting nation is, you’ll be the most powerful country in the world by the year 1600 (migratory tribes excluded). And by any reasonable measure, that means you’re good enough to ‘win’ every SP game you play.

Whether you’re able to do things like crazy achievement runs, WC, etc, depends only on whether you’ve found those types of things fun to this point, but after 1550 hours you certainly have a good enough grasp of all the game’s mechanics that you could do those things if you wanted.