How do you add a Post Process Image Effect pass in URP(apply image effect shader)?

Hello,
I'm trying to implement a glitch iamge effect in URP. I'm using this shader:
http://halisavakis.com/my-take-on-shaders-glitch-image-effect/

But that was written assuming onrenderimage() which is not available on URP. I tried to use custom renderpass but I was unable to make it work.

This is the code:

Code (CSharp):

1. public class GlitchPassFeature : ScriptableRendererFeature
2. {
3.  
4.     class GlitchPass : ScriptableRenderPass
5.     {
6.         private RenderTargetIdentifier sourceCameraTargetIdentifier;
7.         private Material effectMat;
8.         string m_ProfilerTag = "GlitchPass";
9.         RenderTargetHandle m_TemporaryColorTexture;
10.  
11.         public void setup(RenderTargetIdentifier _cameRenderTargetIdentifier, Material mat)
12.         {
13.             sourceCameraTargetIdentifier = _cameRenderTargetIdentifier;
14.             effectMat = mat;
15.         }
16.  
17.         // This method is called before executing the render pass.
18.         // It can be used to configure render targets and their clear state. Also to create temporary render target textures.
19.         // When empty this render pass will render to the active camera render target.
20.         // You should never call CommandBuffer.SetRenderTarget. Instead call <c>ConfigureTarget</c> and <c>ConfigureClear</c>.
21.         // The render pipeline will ensure target setup and clearing happens in an performance manner.
22.         public override void Configure(CommandBuffer cmd, RenderTextureDescriptor cameraTextureDescriptor)
23.         {
24.         }
25.  
26.         // Here you can implement the rendering logic.
27.         // Use <c>ScriptableRenderContext</c> to issue drawing commands or execute command buffers
28.         // https://docs.unity3d.com/ScriptReference/Rendering.ScriptableRenderContext.html
29.         // You don't have to call ScriptableRenderContext.submit, the render pipeline will call it at specific points in the pipeline.
30.         public override void Execute(ScriptableRenderContext context, ref RenderingData renderingData)
31.         {
32.             CommandBuffer cmd = CommandBufferPool.Get(m_ProfilerTag);
33.  
34.  
35.             cmd.Blit(sourceCameraTargetIdentifier, BuiltinRenderTextureType.CurrentActive,effectMat);
36.             context.ExecuteCommandBuffer(cmd);
37.  
38.             cmd.GetTemporaryRT(m_TemporaryColorTexture.id, renderingData.cameraData.cameraTargetDescriptor);
39.             Blit(cmd, sourceCameraTargetIdentifier, m_TemporaryColorTexture.Identifier(), effectMat);
40.             Blit(cmd, m_TemporaryColorTexture.Identifier(), sourceCameraTargetIdentifier);
41.  
42.  
43.             cmd.Release();
44.         }
45.  
46.         /// Cleanup any allocated resources that were created during the execution of this render pass.
47.         public override void FrameCleanup(CommandBuffer cmd)
48.         {
49.  
50.         }
51.     }
52.  
53.  
54.  
55.  
56.     [System.Serializable]
57.     public class GlitchSettings
58.     {
59.         public RenderPassEvent whenToRender = RenderPassEvent.AfterRenderingTransparents;
60.         //RenderPassEvent.AfterRenderingPostProcessing;
61.         public bool enabled = false;//#TODO USE THIS DAMMIT
62.         public Material effectMat;
63.     }
64.  
65.     GlitchPass glitchPass;
66.     public GlitchSettings settings;
67.  
68.  
69.     public override void Create()
70.     {
71.         glitchPass = new GlitchPass();
72.  
73.         // Configures where the render pass should be injected.
74.         glitchPass.renderPassEvent = settings.whenToRender;
75.     }
76.  
77.     // Here you can inject one or multiple render passes in the renderer.
78.     // This method is called when setting Up the renderer once per-camera.
79.     public override void AddRenderPasses(ScriptableRenderer renderer, ref RenderingData renderingData)
80.     {
81.         if(!settings.enabled )
82.             return;
83.         // we're getting the camera's color buffer target
84.         var cameraColorTarget = renderer.cameraColorTarget;
85.         glitchPass.setup(cameraColorTarget,settings.effectMat );
86.         renderer.EnqueuePass(glitchPass);
87.     }
88. }
89.  
90.  
91.  

It seems to blitting something as it ovewrrides the camera background color if I run it before skyboxes are rendered. However, it doesn't change anything else.
When I run it after post processing, It gets rid of the post process bloom but the effect works. However, I need post processing for my game.

How do I integrate an image effect in URP in 2019.4?