HDRP shader and code for depth maps

Hi everyone! I'm quite a beginner in unity, and I'm having some issues trying to make my camera render a depth map of a small landscape with some objects in the foreground (for now just cubes) while using HDRP settings. Searching online, I've found some tutorials and documentation that suggest using a custom shader and a script attached to the camera which renders depth. The problem is that these work perfectly only with the built-in render pipeline, not with HDRP. How can I "upgrade" the shader and the scfript to make them work in HDRP? Here is the shader:

 Shader "Custom/RenderDepth"
 {
     Properties
     {
         _DepthLevel("Depth Level", Range(1, 3)) = 2
     }
         SubShader
     {
         UsePass "Legacy Shaders/VertexLit/SHADOWCASTER"
 
         Pass
         {
             CGPROGRAM
 
             #pragma vertex vert
             #pragma fragment frag
             #include "UnityCG.cginc"
 
             uniform sampler2D_float _CameraDepthTexture;
             uniform fixed _DepthLevel;
             uniform half4 _MainTex_TexelSize;
 
             struct uinput
             {
                 float4 pos : POSITION;
                 half2 uv : TEXCOORD0;
             };
 
             struct uoutput
             {
                 float4 pos : SV_POSITION;
                 half2 uv : TEXCOORD0;
             };
 
             uoutput vert(uinput i)
             {
                 uoutput o;
                 o.pos = UnityObjectToClipPos(i.pos);
                 o.uv = MultiplyUV(UNITY_MATRIX_TEXTURE0, i.uv);
                 return o;
             }
 
             fixed4 frag(uoutput o) : COLOR
             {
                 float depth = UNITY_SAMPLE_DEPTH(tex2D(_CameraDepthTexture, o.uv));
                 depth = pow(Linear01Depth(depth), _DepthLevel);
                 return depth;
             }
 
             ENDCG
         }
     }
 }

And this is the script attached to the camera:

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 [ExecuteInEditMode]
 [RequireComponent(typeof(Camera))]
 public class DepthTextureTest : MonoBehaviour
 {
     public Camera _cam;
     public Material mat;
 
     public float DepthLevel = 1.0F;
 
     void Start()
     {
         _cam.depthTextureMode |= DepthTextureMode.Depth;
     }
 
     void Update()
     {
     }
 
     void OnRenderImage(RenderTexture source, RenderTexture destination)
     {
         mat.SetFloat("_DepthLevel", DepthLevel);
         Graphics.Blit(source, destination, mat);
     }
 
 }

From what I understood, HDRP shaders are written differently and include other functions, while the function depthTextureMode doesn't work at all with HDRP. This is an example of the result I would like to obtain:

Thanks in advance