How to make specific 2D overlay over 3D scene?

Godot Version

4.3 stable

Question

I want to make basic inspect feature.
I have a 3D scene with table and cards on it. Player can interact with card to look closer on it. In that case I want to add 2D overlay that will blur or darken the background EXCEPT the one card/3D object that was selected.

I tried to use CanvasLayers, another inspect scene with viewport and copy of inspected object, etc. But in any case, the ColorRect overlay I use is overlaying all the objects on the screen, no matter what.