Dynamic Texture2D does not render as it should

Hi,

I create a dynamic texture2D("_dynamicTexture") and when I run the scene, the sprite objet does not display the new texture with my shader.

How can I apply it correctly and not get my white ish result(as shown below)?

This is my test code:

 using UnityEngine;
 using System.Collections;
 
 public class Test : MonoBehaviour {
 
     public Color _testColor;
     private Texture2D _dynamicTexture;
     
     private void Start(){
         Sprite selfSprite = GetComponent<SpriteRenderer> ().sprite;
         int width = (int)(selfSprite.bounds.max.x - selfSprite.bounds.min.x);
         int height = (int)(selfSprite.bounds.max.y - selfSprite.bounds.min.y);
         
         _dynamicTexture = new Texture2D (width, height, TextureFormat.ARGB32, false);
 
         DrawToTexture ();
     }
     
     private void Update(){
         // This part is fully functionnal and was test with other texture
         // assigned via the Unity developpement interface
         renderer.sharedMaterial.SetTexture ("_ResultingTex", _dynamicTexture);
     }
     
     private void DrawToTexture(){
         for(int x = 0; x < 64; x++)  //hardcoded value for question purpose
         {
             for(int y = 0; y < 64; y++)  //hardcoded value for question purpose
             {
                 _dynamicTexture.SetPixel(x, y, _testColor);
             }
         }
     }
 }

The anticipated result should look like this:

Finally this is the Unity UI showing the before and after i run the test, just so you can view the whole thing(which is very simple in fact):