This is actually a bit more complicated. Check for example how this case is treated in HTML5 spec and what problems has to be solved.
https://www.w3.org/TR/html50/text-level-semantics.html#the-bdi-element
Hi Kamil Dyrek,
Welcome to Affinity Forums :)
Thanks for your feedback. Regarding dragging items over another items, you don't have to aim beneath the targeted group. You can simply drop the item over the main target layer and it will be placed as a child. In there any case you can't do it?
Regarding your second question about selecting objects over other objects - without any object selected press and hold ⌥ (option/alt) then start drawing the marquee around the objects you want to select. This will do want you want.