fit spriterenderer image to screen after change aspect ratio

hello! i'll try to explain what i have... my "field" camera with this script (used to keep the aspetct)

 using UnityEngine;
  
 [RequireComponent(typeof(Camera))]
 public class CameraCrop : MonoBehaviour {
  
     // Set this to your target aspect ratio, eg. (16, 9) or (4, 3).
     public Vector2 targetAspect = new Vector2(16, 9);
     Camera _camera;
  
     void Start () {
         _camera = GetComponent<Camera>();
         UpdateCrop();
     }
  
     // Call this method if your window size or target aspect change.
     public void UpdateCrop() {
         // Determine ratios of screen/window & target, respectively.
         float screenRatio = Screen.width / (float)Screen.height;
         float targetRatio = targetAspect.x / targetAspect.y;
  
         if(Mathf.Approximately(screenRatio, targetRatio)) {
             // Screen or window is the target aspect ratio: use the whole area.
             _camera.rect = new Rect(0, 0, 1, 1);
         }
         else if(screenRatio > targetRatio) {
             // Screen or window is wider than the target: pillarbox.
             float normalizedWidth = targetRatio / screenRatio;
             float barThickness = (1f - normalizedWidth)/2f;
             _camera.rect = new Rect(barThickness, 0, normalizedWidth, 1);
         }
         else {
             // Screen or window is narrower than the target: letterbox.
             float normalizedHeight = screenRatio / targetRatio;
             float barThickness = (1f - normalizedHeight) / 2f;
             _camera.rect = new Rect(0, barThickness, 1, normalizedHeight);
         }
     }
 }

and one more camera inside my canvas used to who 3d character on UI and a background image ( used to show a screenshot got from the field camera) so what i have on my ui is 3d model with a background spriterenderer with a screenshot texture got from "field" camera ( using rendertexture )

on cap1 is what i have on my "field" camera then i take a screenshot and on cap2 is what i have after i get a screenshot with the rendertexture then convert it to a texture2d and create a new sprite from that texture ( to a sprite render inside the canvas camera)

so as you can see the screenshot doesn't fit the entire screen, without the above script it does fit perfectly.

this is what i do to resize it

     void ResizeSpriteToScreen()
     {
         SpriteRenderer sr = sprite.GetComponent<SpriteRenderer>();
  
         sprite.transform.position = _myCamera.transform.position + Vector3.forward * sr.transform.position.z;
  
         sprite.transform.localScale = new Vector3(1, 1, 1);
         Vector3 lossyScale = sprite.transform.lossyScale;
  
         float width = sr.sprite.bounds.size.x;
         float height = sr.sprite.bounds.size.y;
  
         float worldScreenHeight = _myCamera.orthographicSize * 2f;
         float worldScreenWidth = worldScreenHeight / Screen.height * Screen.width;
  
         Vector3 xWidth = sprite.transform.localScale;
         xWidth.x = worldScreenWidth / width;
         sprite.transform.localScale = xWidth;
         //transform.localScale.x = worldScreenWidth / width;
         Vector3 yHeight = sprite.transform.localScale;
         yHeight.y = worldScreenHeight / height;
         sprite.transform.localScale = yHeight;
  
         Vector3 newLocalScale = new Vector3(transform.localScale.x / lossyScale.x,
             sprite.transform.localScale.y / lossyScale.y,
             sprite.transform.localScale.z / lossyScale.z
         );
  
         sprite.transform.localScale = newLocalScale;
     }