Noise Cancellation seems to be worse and lets in more background noise

I have used the Noise Cancellation feature on my AirPods Pro 2nd generation for a few years now. However, recently they seem to be letting more background noise even when noise cancellation is on. This seems to happen especially at higher frequencies - for example I can now hear my mouse click with noise cancellation enabled when I couldn’t before. I could also hear more of the gym music when trying to listen to my own music so definitely not ideal!

Has anyone else noticed this?

I wonder if maybe the new features provided by the latest firmware upgrade take up more of the limited onboard processing power, therefore leaving less available for ANC?

Or maybe Apple just changed the ANC algorithm altogether?

Thanks in advance!

(Just to clarify, I have already tried cleaning the mic vents, etc. but still noticed this behaviour)