I have been submitting my runs in the Ultimate Emperor category but the top run there is easy mode and mine is hard. How could I sort this out?

Normally you can pick whatever difficulty you like, so in this case your hard run will be measured as equal to Valenthtain's easy. If hard and easy differs enough we can split them into two different categories, but I'm unsure what parameters are tweaked and if the difference is big enough. Other than the AI probably being more aggressive how is the two difficulties different?

Difference is in easy mode any peasant army can take an unsecured settlement(given enough luck, as you need to do this at least 7 times) and immediately the country is down to became your vassal. In hard difficulty that wont work. Only way to get a vassal with one peasant army is to go there, avoid any fights and plunder as much as possible hoping for the enemy to get exhausted and give up. this can take a lot of time tho. Also in easy mode, when you declare war, enemies rarely try to attack, while in hard mode the first thing they try is offensive. I don't know if it's worth creating a separate category. I am already planning the easy mode run just a shame as my hard mode run becomes obsoleted by my easy mode run.

I've played this game for more than 400 hours and to be honest, I don't see much difference. The country can also be conquer1 peasant army on easy. I do not see the point in this category to make a division of difficulties because it is not worth it. The time and complexity will be + - the same difference will be a couple of minutes, and sometimes it will not even be because it all depends on luck. In my passage, I made the 11+- vassals because the old ones died and could not stay in the top. Although this is purely random. You can divide the difficulty in the world capture category. That's where it will be more useful and more difficult to achieve a high " indicator"

The mod already decided they won't do the hard category.

Doing the exact thing I did in my run but in easy saves me like 10 minutes. It can't all be luck right?

With 400 hours you should know this but I had to make sure: The vassals who aren't in the top anymore can be brought back up if you give them a land or two.

Unfortunately, in this category approximately 60-80% of success depends purely on your luck, provided that you are trying to achieve the maximum indicator. You are of course right that if you give a territory or give a lot of money to a vassal, then he will return to the rating, but this is still time + a waste of resources, and you have more than one vassal.