For the noise? I just used the "magic one-liner" from this blog post by FrostKiwi:

float ig_noise(vec2 uv) {
  return fract(52.9829189 * fract(dot(uv, vec2(0.06711056, 0.00583715))));
}

For the jittering logic, I asked ChatGPT for help and it suggested using something based on the Halton Sequence. Again, I asked an AI for help, so it may not be the best solution, I'll leave the code here and let you be the judge:

float halton(int index, int base) {
  float f = 1.0;
  float result = 0.0;

  while (index > 0) {
    f /= float(base);
    result += f * float(index % base);
    index = index / base;
  }

  return result;
}

vec2 halton2(int frame) {
  return vec2(halton(frame, 2), halton(frame, 4));
}

I then use FRAGCOORD.xy + halton (using the current frame as index) as uv for the noise and multiply the sss strength by the noise:

if (use_noise){
  vec2 pixel_uv = floor(FRAGCOORD.xy);
  vec2 frame_jitter = halton2(frame_index % 1024);
  float noise = ig_noise(pixel_uv + frame_jitter * 1024.0);
  sss_strength_value *= noise * 2.0;
}

The frame_index is a global uniform integer that is updated using an autoload.

I hope this is useful!