[Pro] How do I make programmatic Render-to-Texture work?

Simple scene, one camera, to which I attach this script:

 using UnityEngine;
 
 public class BzSetupCam : MonoBehaviour {
 
     private RenderTexture rtt;
 
     void Start () {
         camera.layerCullSpherical = true;
         rtt = new RenderTexture(Screen.width / 4, Screen.height / 4, 16, RenderTextureFormat.Default, RenderTextureReadWrite.Default);
         rtt.filterMode = FilterMode.Point;
         // rtt.wrapMode = TextureWrapMode.Clamp;
         rtt.anisoLevel = 0;
         rtt.antiAliasing = 1;
         camera.targetTexture = rtt;
     }
     
     void OnDestroy() {
         Destroy(rtt);
     }
     
     void OnPreRender() {
         if (!rtt.IsCreated()) {
             if (!rtt.Create()) {
                 Debug.LogError("Failed to create RTT");
             }
         }
     }
 
 }

Since the only cam has thusly been re-targeted from "screen" to "render texture", I now see nothing, this was to be expected.

Now what's the smartest way to blit this to the screen when the render texture is completed?

• Do I need a 2nd camera with an orthographic quad mesh bound to a material that's linking a simple Tex2d-sampling pixel shader?

• Or is there a one-liner command for stuff like this?

Just need to show the render texture scaled to full screen to get dat pixelated style the "cheap way" (rather than post-pixelating a full 1080p screen image after the fact via image-effect as many seem to do).