Awesome, so many options!
But for the moment Alt+ Right Mousedrag works great for me

Also is it possible to make somehow a selection like in the screenshot (to select the little circles and the brakets) without selecting anything else behind it?
Because when I try to click and mouse drag, it is selecting and dragging the object behind it.
I know that i can make selections when I click and drag on a "empty" field from left to right and vise versa.
https://ibb.co/tCLTYvm

But what to do when there are objects behind it and I only want to select some circles in that case.

With the other views 8top(right/front) there are also objects all around so I don't have "empty" space.