2D mobile resolution problem (screen is displayed like mosaic or blur)

Hello

My 2D unity game looks strange on mobile platfrom. it looks fine on editor but only happends on mobile.

There're some solutions I tried but nothing worked..

-changing pixel per unit

-changing resolution of Canvas

• build options are set as 64bit

-changing all sprite inspector as Sprite 2D and UI / single / adjust pixels per unit /No filter / Compression None

• Insert this Camera script below in camera.

     public class CameraScript : MonoBehaviour
       {
           private void Start()
           {
               Camera camera = GetComponent<Camera>();
               Rect rect = camera.rect;
               float scaleheight = ((float)Screen.width / Screen.height) / ((float)9 / 16);
               float scalewidth = 1f / scaleheight;
               if (scaleheight < 1)
               {
                   rect.height = scaleheight;
                   rect.y = (1f - scaleheight) / 2f;
                    
               }
               else
               {
                   rect.width = scalewidth;
                   rect.x = (1f - scalewidth) / 2f;
               }
               camera.rect = rect;
           }
           void OnPreCull() => GL.Clear(true, true, Color.black);
  
  
  

If you know how to solve this problem, or have any recommendation. Please help me. Thank you for your attention and kind help.