The navigator sometimes doesnt show elements that are selected, and when it does, the color of the element selected is not clear enough to see right away, especially when there are a lot of elements on the page.

The clutter would also be helped by a filter, so you can set which device you are looking at. Rest devices with their elements should be hidden.

If I'm editing desktop, why do I care for elements on mobile? They are just clutter at that point.

Sure, a buton to show all can be added for people who prefer that.