Please excuse in the case of misunderstanding your ask.
I've always liked https://www.rastertek.com/tutdx11win10.html 

I agree that the diagram is hard to read. Make the text bigger, and make the arrows bigger, and label the arrows for what they mean. Ownership? Communication? Reactivity? Dependency? Usage?

But, also, I think your architecture diagram seems to mix a bunch of different layers of abstraction.

How about…

@Jikoob If it works for you then there isn't anything really wrong with it.

Myself I use an asset manager that handles anything that can fit under the category of an asset, images, sound, fonts, models, maps, …

If you make a generic enough manager you can simply add an interface to allow new asset ty…

@Juliean Thank you this is useful. It has changed my way of thinking and approaching my engine. 

Dreadpon said:
Did anyone try to solve this already?

People have had good solutions for several decades now. The problem isn't new.

Dreadpon said:
Surely there aren't 2 separate UI systems that are hardcoded into each edition of the game?

Two? No, that number is far too low. Often the ratios are 4:3, 3:…