How to correct blurry UI? Or duplicate the camera? also clean render texture.

Hello unity masters,

I'm working on an UI project and I want to copy my ui, blurry it and put it behind the same Ui.
I setup a camera that only render the canvas Ui, screen space camera if I'm not wrong.

Right now is working but I'm pretty sure I'm doing it wrong.
In my code I create a render texture, then in my Update code I save the camera render in targettexture in low resolution (fake blurry), after that I null the target texture, if I don't do this part my ui don't render at all.

After I got my render texture in low res I just put it inside a raw texture in my canvas with an add shader and upscale.

It's feel really wrong to do this on update... there is no other way to render the camera inside a texture and keep the camera rendering on screen? I saw something about temporarytexture but I didn't find any code example.

Also, my render texture never clear, so every time I press play my texture rewrite the older one giving some ghost effect, liking adding images together.

I'm very lost, Appreciate any help!

 

So i did it.

This was the technique;
1 Camera to the BG - render in texture
1 Camera to the UI - render in texture
1 Camera that do blit, taking the texture from BG and UI and render to screen.

In the shader i take the BG and attach the UI (blurried) to it, using lerp.
from the (BG+ UI blurry ) lerp i do another lerp with the UI not blurry.

After that i add the Post proccess stack.
It works well and the colors are mostly the same.

I still want to find a way to Layer those texture in the shader, going to make another post for that. The lerp solution works but is not perfect. maybe using a second pass?