How can I rotate/orbit the camera around an object?

Hello new unity developer here trying to figure out how I can orbit/rotate the camera around my player object when the right mouse button is being held down (so hold right click, move mouse around to move the camera). So far I did manage to get things to work, however it's a bit scuffed when rotating it seems like the camera goes upsidedown or something so wanted to know how I can improve this.

     public Transform focus;
     public float sensitivity = 1;
     public float speed = 30;
     public float zoomLevel;
     public float zoomPosition;
     public bool rotateCamera = false;
 
     void Update()
     {
         if (Input.GetMouseButtonDown(1))
         {
             Debug.Log("Right Mouse Button Clicked");
             Cursor.visible = false;
             rotateCamera = true;
         }
 
         if (Input.GetMouseButtonUp(1))
         {
             Debug.Log("Right Mouse Button Released");
             Cursor.visible = true;
             rotateCamera = false;
         }
 
         if (rotateCamera)
         {
             //Let the player drag the camera around (360 degrees/orbit idk)
             //when they let go of right click camera will stay in the position they left it in.
             transform.eulerAngles += 10 * new Vector3(Input.GetAxis("Mouse Y"), Input.GetAxis("Mouse X"), 0);
         }
 
         //Camera Zoom
         zoomLevel += Input.mouseScrollDelta.y * sensitivity;
         zoomLevel = Mathf.Clamp(zoomLevel, -30, 0); 
         zoomPosition = Mathf.MoveTowards(zoomPosition, zoomLevel, speed * Time.deltaTime);
         transform.position = focus.position + (transform.forward * zoomPosition);