How to bind a 2D camera and its resolutions to physical. object?

Question

C++ / C#

How to bind a 2D camera, or rather all its possible vertical screen resolutions, to an object that is not a UI , that is, not located in the canvas. This object is not an option to make a UI, since other objects appear on it at certain coordinates. They just appear on stage.
It is necessary that the binding is carried out in width, i.e. The camera object was always flush-aligned to its sides.