Terrain texture low quality

Hi.

I discovered this shader:
// Upgrade NOTE: replaced '_Object2World' with 'unity_ObjectToWorld' // Upgrade NOTE: replaced '_World2Object' with 'unity_WorldToObject'

  Shader "Custom/CurvedWorld" {
      Properties {
          // Diffuse texture
          _MainTex ("Base (RGB)", 2D) = "white" {}
          // Degree of curvature
          _Curvature ("Curvature", Float) = 0.001
      }
      SubShader {
          Tags {
      "Queue" = "Transparent"
      "RenderType"="Transparent" }
          LOD 200
   
          CGPROGRAM
          // Surface shader function is called surf, and vertex preprocessor function is called vert
          // addshadow used to add shadow collector and caster passes following vertex modification
          #pragma surface surf Lambert vertex:vert addshadow
   
          // Access the shaderlab properties
          uniform sampler2D _MainTex;
          uniform float _Curvature;
   
          // Basic input structure to the shader function
          // requires only a single set of UV texture mapping coordinates
          struct Input {
              float2 uv_MainTex;
          };
   
          // This is where the curvature is applied
          void vert( inout appdata_full v)
          {
              // Transform the vertex coordinates from model space into world space
              float4 vv = mul( unity_ObjectToWorld, v.vertex );
   
              // Now adjust the coordinates to be relative to the camera position
              vv.xyz -= _WorldSpaceCameraPos.xyz;
   
              // Reduce the y coordinate (i.e. lower the "height") of each vertex based
              // on the square of the distance from the camera in the z axis, multiplied
              // by the chosen curvature factor
              vv = float4( 0.0f, (vv.z * vv.z) * - _Curvature, 0.0f, 0.0f );
   
              // Now apply the offset back to the vertices in model space
              v.vertex += mul(unity_WorldToObject, vv);
          }
   
          // This is just a default surface shader
          void surf (Input IN, inout SurfaceOutput o) {
              half4 c = tex2D (_MainTex, IN.uv_MainTex);
              o.Albedo = c.rgb;
              o.Alpha = c.a;
          }
          ENDCG
      }
      // FallBack "Diffuse"
  }

Only think what i did is change Queue and Render Type to transparent. I want to create terran which allow transparentcy. After that change it working. But when testing it i discoverd big problem.
Textures are very blur and won't help changing size of textures.
Here is image:

What can i do with it? Use different shader?
If i must use different shader then is it problem because any other shader won't work correctly. I tryed many of shaders but every have some bad effects. Every support only 4 textures and i don't know how to increase this number.
Thank all.

Have a nice day. Marks