Move object with finger swipe

I've been trying to program a way to make an object move with your finger, no matter where it is on the screen. So, if you move your finger (anywhere vertically, doesn't have to be on the object) from the middle of the screen to the right side of the screen, the object will move half a screen to the right also, where ever it is.

This is the code that I'm currently using but it doesn't work correctly, the move of the object varies between screen sizes/DPI's.

         if (Input.touchCount == 1)
         {
             Touch touch  = Input.GetTouch(0);
             
             if (touch.phase == TouchPhase.Began)
             {
                 leftFingerPos = Vector2.zero;
                 leftFingerLastPos = Vector2.zero;
                 leftFingerMovedBy = Vector2.zero;
                 
                 slideMagnitudeX = 0;
                 slideMagnitudeY = 0;
                 
                 // record start position
                 leftFingerPos = touch.position;
                 
             }
             
             else if (touch.phase == TouchPhase.Moved)
             {
                 leftFingerMovedBy = touch.position - leftFingerPos; // or Touch.deltaPosition : Vector2
                 // The position delta since last change.
                 leftFingerLastPos = leftFingerPos;
                 leftFingerPos = touch.position;
                 
                 // slide horz
                 slideMagnitudeX = leftFingerMovedBy.x / Screen.width;
                 
                 // slide vert
                 slideMagnitudeY = leftFingerMovedBy.y / Screen.height;
                 
             }
             
             else if (touch.phase == TouchPhase.Stationary)
             {
                 leftFingerLastPos = leftFingerPos;
                 leftFingerPos = touch.position;
                 
                 slideMagnitudeX = 0.0f;
                 slideMagnitudeY = 0.0f;
             }
             
             else if (touch.phase == TouchPhase.Ended || touch.phase == TouchPhase.Canceled)
             {
                 slideMagnitudeX = 0.0f;
                 slideMagnitudeY = 0.0f;
             }
 
 
             gameObject.transform.position = new Vector3(gameObject.transform.position.x + slideMagnitudeX, gameObject.transform.position.y + slideMagnitudeY, gameObject.transform.position.z);
         }