According to this page, [1] it reduces unwanted noise 4x as much as the original AirPods Pro and 2x as much as the AirPods Pro 2.

Though I do wonder, given the logarithmic nature of sound perception, are these numbers deceptive in terms of what the user will perceive?

1: https://www.apple.com/airpods-pro/

It was 4x over the original version IIRC so should be ~ 2x over the previous