Scene Lag when first running a certain script, but then returns to normal performance afterwards?

I have a script for my player's input. The profiler is reading that the Update method for that script is using too much CPU and lags the scene quite alot when it is first used, however after it has run the fist time, the performance returns back to the normal desired speed. after running the script the first time there is no lag when running it again. I am a bit confused and would like to know how I can optimize this script to run at the normal speed the first time when the scene is loaded.

Below Is the update method for that script. Please comment if you have any suggestions or experience with this sort of thing. Thank you.

 void Update() 
         {
             float scrollWheel = Input.GetAxis("Mouse ScrollWheel");
             camController.Zoom(scrollWheel);
             bool Grounded = player.checkGroundcontact();
     
             if(!isArmDragging && HandlePinchToZoom())
             {
                 isCameraDragging = false;
                 return;
             }
     
             if(!Grounded)
             {
                 camController.MoveTo(player.CamTarget.transform.position);
             }
             if (Input.GetMouseButtonDown(0) && Grounded) 
             {
                 camController.StorePosition();
     
                 Vector3 mouseScreenPos = Input.mousePosition;
                 Vector3 mouseWorldPos = Camera.main.ScreenToWorldPoint(mouseScreenPos);
                 Collider2D hit = Physics2D.OverlapPoint(mouseWorldPos, LayerMask.GetMask("Arm Click"));
     
                 if (hit != null)
                 {
                         isArmDragging = true;
                         mouseScreenPos = Camera.main.WorldToScreenPoint(player.flingOffsetStartTransform.position);
                         mouseScreenPos.z = 0;
                 } 
                 else 
                 {
                     isCameraDragging = true;
                 }
     
                 mouseDragStart = mouseScreenPos; // in screen space
             } 
     
             else if (Input.GetMouseButton(0) && Grounded) 
             {
                 if(isArmDragging) 
                 {
                     Vector3 delta = ScreenToWorldDelta(Input.mousePosition, mouseDragStart);
                     delta = ConstrainDelta(delta);
                     delta = TransformDelta(delta);
                     if (aimingTracker != null) 
                     {
                         aimingTracker.MouseDragged(delta);
                     }
     
                     player.UpdateAiming(delta, GetNormalizedDelta(delta));
                     player.graphics.Stretchy.SetActive(true);
                     player.graphics.Transitions.SetActive(false);
                 }
                 else if(isCameraDragging) 
                 {
                     Vector3 delta = ScreenToWorldDelta(Input.mousePosition, mouseDragStart);
                     if(invertCamera)
                     {
                         camController.UpdatePosition(delta);
                     }
                     else
                     {
                         camController.UpdatePosition(-delta);
                     }
                 }
     
             } 
     
             else if (Input.GetMouseButtonUp(0) && Grounded) 
             {
                 if(isArmDragging) 
                 {
                     Vector3 delta = ScreenToWorldDelta(Input.mousePosition, mouseDragStart);
                     delta = ConstrainDelta(delta);
                     delta = TransformDelta(delta);
     
                     if(aimingTracker != null) 
                     {
                         aimingTracker.EraseDots();
                     }
                     if(player != null) 
                     {
                         player.graphics.Stretchy.SetActive(false);
                         player.graphics.Transitions.SetActive(true);
                         player.graphics.Prelaunch(delta);
                         player.ApplyForce(delta);
                         player.graphics.Ignite();
                     }
                 }
                 else if (isCameraDragging)
                 {
                     camController.EndDrag();
                 }
                 isArmDragging = false;
                 isCameraDragging = false;
                 mouseDragStart = new Vector3(0,0,0);
             }
         }