They’ve been many reports on Apple’s forums (https://discussions.apple.com/thread/250887615) and on reddit (https://www.reddit.com/r/airpods/comments/ebjadh/new_firmware_released_for_gen2_and_pro_models/) that the first and second firmware updates have massively reduced ANC performance from the out the box version. There’s also been discussion that they sound slightly different.
Could you kindly do a re-test of your isolation performance and frequency sweeps like you did to test the XM3 and Bose QC35ii’s that had similar reports?
I’m an Android/Windows user so I’m still on the factory firmware and am enjoying the ANC. I don’t want to risk an update if it changes that - but I also understand so much of this is subjective as your XM3 results show there was no difference.
Thank you kindly :)