Simple inefficient postprocess in WEBXR

Hi everyone,
I know there’s no an efficient outofthebox solution for postprocessing in WebXr.
Anyway maybe someone could suggest some easy alternative to implement what I’m looking for: I need to dynamically decrease resolution of the render as the camera move away from the scene origin.

I try to implement this codesandbox:

(just a basic variation from the Cody Bennet one: WebXR - postprocessing - CodeSandbox)

When I use a webxr emulator I can correctly see the two side by side render, but sadly when I try it with a Pico4 the scene renders black as soon as I uncomment the component.

This is the desktop version of my final project (realized in r3f): basically moving away form the central tower the player experiences a general decrease in performance
https://floating-realities-cyqxeeyf6-paolocorti87.vercel.app/carminati

This is one of the rare cases in which deteriorating performance is not a problem but the goal
Maybe someone could point me in the right direction… :white_heart: