the bar is at least 4cm away from the wall.

Hello
I don't understand the question. You can adjust the height, because at the lowest setting, the bottom of the screen touches the skin.

I don't quite understand your question either. But the bracket for the monitor can be moved up and down the entire length of the bar. However, the subsequent height adjustment is a bit fiddly.

Hello Bilmerte,

I don't understand your question. What do you mean by the axis of the screen?
It depends on how big your screen is.