Raycasting on render texture, minimap

Hi. I am trying to make interactable minimap. I am using Raw image canvas to hold the second camera and RenderTexture to display the output of the second camera.

I have tried using secondcamera.ScreenPointToRay(input.mousepos) but that does not work. I cant make the raycast to detect the second camera (canvas/render texture).

I believe that interactable minimap such as this is very common in games and there must be some general workaround for this, that is widely and always used. I need to get hover over effect on the units displayed in minimap.

What I've tried so far:

 public void CamTest()
     {
         if (Input.GetMouseButton(1))
         {
 
             RaycastHit hit;
             Ray ray = SecondCamera.ScreenPointToRay(Input.mousePosition);
 
             if (Physics.Raycast(ray, out hit))
             {
                 Debug.Log(hit.transform.name);
 
 
             }
         }
     }

But I just cant get a callback from the canvas/renderTexture what so ever. I have read on the forums that I should use the coordinates from the second camera and based on them, cast a ray from the first camera , to get the clickable object on minimap. This seems to be way too complicated for such an easy thing and It wont work for me, since I cant raycast on the minimap at all :( Thanks for the help.