TPS Camera roll ball

Hi everyone,

I'm currently trying to make a rolling ball 'platform' game where you have to finish the route to win.
It looks like this:

Let's me explain how it's working. You can move the camera horizontally by pushing left and right button, you will rotate around the ball. There is the code :

 transform.RotateAround(target.transform.position, (cammovement), Time.deltaTime *smooth);

To move on the ball will follow the camera direction by adding a force when you use top and down button. Here it is (with rbT as the target Rigidbody):

  void RollBall()
     {
         //set force down camera's look direction
         forceDirection = transform.forward;
 
         //remove y force direction for angled camera
         forceDirection = new Vector3(forceDirection.x, 0, forceDirection.z);
 
         if(Input.GetAxis("Vertical") != 0)
         {
       
                 //add force to ball
                 rbT.AddForce(forceDirection.normalized * speed * (Input.GetAxis("Vertical")));
                 
         }
 } 

My first problem was that the camera doesn't follow the ball even it still rotating around. I experimented that we cannot use transform.position and transform.RotateAround in the same code/GameObject.

So I decided to put the Camera inside an Empty GameObject and force the GO to follow the ball using a classic transform position + offset and it's worked pretty well. void LateUpdate() { transform.position = player.transform.position + offset; }

But now I'm trying to manage the collision between the camera and the terrain. I have found a tutorial which explains that easily and I implemented it in, but of course, it contains a transform.position and it's not working on the GO parent (which is not rotating).

There is the experimentation code:

 void Update()
     {
         if(Input.GetAxis("Vertical") != 0)
         {
             desiredCameraPosition = transform.TransformPoint(maxDistance * (Cam.transform.forward * Input.GetAxis("Vertical")));
         }
         //desiredCameraPosition = transform.TransformPoint(dollyDir * maxDistance);
         RaycastHit hit;
         Debug.DrawLine(Cam.transform.position, desiredCameraPosition, Color.green);
 
 
         if (Physics.Linecast(Cam.transform.position, desiredCameraPosition, out hit))
         {
             Debug.Log("1");
             distance = Mathf.Clamp((hit.distance*0.7f), minDistance, maxDistance);
         }
         else
         {
             Debug.Log("2");
 
             distance = maxDistance;
         }
 
        Cam.transform.position = Vector3.Lerp(Cam.transform.localPosition, dollyDir * distance, Time.deltaTime * smooth);
     }

So that is my question. How can I manage the camera rotation and using the transformation position to avoid passing thought the terrain and still be able to rotate around my ball?