How to create a zoomable canvas image in Unity for mobile without scaling the main camera?

I have GameObject with Scroll Rect and Rect Mask in my canvas and there is an image in it. I want to zoom in and zoom out of that image. However I don't want to scale Main Camera because there will be other objects in the screen that I don't want to zoom. I searched it but all the tutorials are doing that by scaling Main Camera.

This video is exactly what I want but it doesn't work in android. https://www.youtube.com/watch?v=BFX3FpUnoio&ab_channel=JasonWeimann

This is the script in that video which is added to "image". I tried to modify it but I messed it up. How can I make it work in mobile?

using UnityEngine;
using UnityEngine.EventSystems;

public class UIZoomImage : MonoBehaviour, IScrollHandler
{
    private Vector3 initialScale;

    [SerializeField]
    private float zoomSpeed = 0.1f;
    [SerializeField]
    private float maxZoom = 10f;

    private void Awake()
    {
        initialScale = transform.localScale;
    }

    public void OnScroll(PointerEventData eventData)
    {
        var delta = Vector3.one * (eventData.scrollDelta.y * zoomSpeed);
        var desiredScale = transform.localScale + delta;

        desiredScale = ClampDesiredScale(desiredScale);

        transform.localScale = desiredScale;
    }

    private Vector3 ClampDesiredScale(Vector3 desiredScale)
    {
        desiredScale = Vector3.Max(initialScale, desiredScale);
        desiredScale = Vector3.Min(initialScale * maxZoom, desiredScale);
        return desiredScale;
    }
}

-------UPDATE---------

I found this in Unity forum: https://answers.unity.com/questions/1280592/pinch-and-zoom-functionality-on-canvas-ui-images.html

It almost works but I need to pinch the screen 2-3 to zoom in or zoom out. On first touch nothing happens. It's so annoying. I tried to change _minZoom, _maxZoom, speed and sensitivity values but didn't work.

This is the script there:

using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 using UnityEngine.UI;
 public class PinchableScrollRect : ScrollRect
 {
     [SerializeField] float _minZoom = .1f;
     [SerializeField] float _maxZoom = 10;
     [SerializeField] float _zoomLerpSpeed = 10f;
     float _currentZoom = 1;
     bool _isPinching = false;
     float _startPinchDist;
     float _startPinchZoom;
     Vector2 _startPinchCenterPosition;
     Vector2 _startPinchScreenPosition;
     float _mouseWheelSensitivity = 1;
     bool blockPan = false;
 
     protected override void Awake()
     {
         Input.multiTouchEnabled = true;
     }
 
     private void Update()
     {
         if (Input.touchCount == 2)
         {
             if (!_isPinching)
             {
                 _isPinching = true;
                 OnPinchStart();
             }
             OnPinch();
         }
         else
         {
             _isPinching = false;
             if (Input.touchCount == 0)
             {
                 blockPan = false;
             }
         }
         //pc input
         float scrollWheelInput = Input.GetAxis("Mouse ScrollWheel");
         if (Mathf.Abs(scrollWheelInput) > float.Epsilon)
         {
             _currentZoom *= 1 + scrollWheelInput * _mouseWheelSensitivity;
             _currentZoom = Mathf.Clamp(_currentZoom, _minZoom, _maxZoom);
             _startPinchScreenPosition = (Vector2)Input.mousePosition;
             RectTransformUtility.ScreenPointToLocalPointInRectangle(content, _startPinchScreenPosition, null, out _startPinchCenterPosition);
             Vector2 pivotPosition = new Vector3(content.pivot.x * content.rect.size.x, content.pivot.y * content.rect.size.y);
             Vector2 posFromBottomLeft = pivotPosition + _startPinchCenterPosition;
             SetPivot(content, new Vector2(posFromBottomLeft.x / content.rect.width, posFromBottomLeft.y / content.rect.height));
         }
         //pc input end
 
         if (Mathf.Abs(content.localScale.x - _currentZoom) > 0.001f)
             content.localScale = Vector3.Lerp(content.localScale, Vector3.one * _currentZoom, _zoomLerpSpeed * Time.deltaTime);
     }
 
     protected override void SetContentAnchoredPosition(Vector2 position)
     {
         if (_isPinching || blockPan) return;
         base.SetContentAnchoredPosition(position);
     }
 
     void OnPinchStart()
     {
         Vector2 pos1 = Input.touches[0].position;
         Vector2 pos2 = Input.touches[1].position;
 
         _startPinchDist = Distance(pos1, pos2) * content.localScale.x;
         _startPinchZoom = _currentZoom;
         _startPinchScreenPosition = (pos1 + pos2) / 2;
         RectTransformUtility.ScreenPointToLocalPointInRectangle(content, _startPinchScreenPosition, null, out _startPinchCenterPosition);
 
         Vector2 pivotPosition = new Vector3(content.pivot.x * content.rect.size.x, content.pivot.y * content.rect.size.y);
         Vector2 posFromBottomLeft = pivotPosition + _startPinchCenterPosition;
 
         SetPivot(content, new Vector2(posFromBottomLeft.x / content.rect.width, posFromBottomLeft.y / content.rect.height));
         blockPan = true;
     }
 
     void OnPinch()
     {
         float currentPinchDist = Distance(Input.touches[0].position, Input.touches[1].position) * content.localScale.x;
         _currentZoom = (currentPinchDist / _startPinchDist) * _startPinchZoom;
         _currentZoom = Mathf.Clamp(_currentZoom, _minZoom, _maxZoom);
     }
 
     float Distance(Vector2 pos1, Vector2 pos2)
     {
         RectTransformUtility.ScreenPointToLocalPointInRectangle(content, pos1, null, out pos1);
         RectTransformUtility.ScreenPointToLocalPointInRectangle(content, pos2, null, out pos2);
         return Vector2.Distance(pos1, pos2);
     }
 
     static void SetPivot(RectTransform rectTransform, Vector2 pivot)
     {
         if (rectTransform == null) return;
 
         Vector2 size = rectTransform.rect.size;
         Vector2 deltaPivot = rectTransform.pivot - pivot;
         Vector3 deltaPosition = new Vector3(deltaPivot.x * size.x, deltaPivot.y * size.y) * rectTransform.localScale.x;
         rectTransform.pivot = pivot;
         rectTransform.localPosition -= deltaPosition;
     }
 }