Thank you very much for your time.
Yeah I had this impression, unfortunately games are not made just using UI, although in Unity would be possible to make a game using the UI system.
How I said I had the same problem in Unity at the end I made an algorithm that was able to re-size the object according to the screen sizes, for most of the mobile platform worked, but it didn't for web and desktop so I had two algorithm one for the mobile and one for the others, it took my a while to figure it out a working solution, something that I was expecting to have from the engine.
In my opinion, is the camera concept that doesn't work for 2D games especially for that kind of games in which you do not really need a camera, like arkanoid style, would be great to have a game engine supporting this kind of different design concept.
About the normalisation, I am aware of those functions, it's quite common in most of the game engines, but what I was saying is about the way of making the object where I shouldn't use any API or so.
Eg. if I know that my asset has a dimension and in my game I would like to have it as 0.2 (0 - 1) I should call a function that is obj.setDim(0.2), and the game engines resize the content based on screen dimension, where my object would be always 0.2 of it.
Anyway, this could be easily going for ever and ever, after this info I guess that Atomic at this stage is not what I am looking for, I will always keep an eye on it but I would like to use game engines that have this kind of screen features.