Has AirPods Pro 2 noise cancelling got weaker?

Yes. It seemed to get worse when they introduced the hearing aid functionality.

I am experiencing the same problem. Happened basically overnight.

I tried cleaning the headphones, resetting the headphones, everything in my power to fix this, but nothing helped. Recently noise cancellation got so bad that I often have to check if it is on at all. I can hear everything coming through. Noise cancellation got so bad in fact that I stopped wearing my AirPods Pro 2-s on the bus because there is no point in doing so anymore. The bus is the same loud.

Amazingly, transparency got way louder at the same time and resulted in my ears hurting whenever I only had a single AirPod in.

Yep, same. I used to not be able to hear my garbage disposal while I had my AirPods in. Now I can hear everything. Apple sent me a new pair, same thing. Apple quality has really gone downhill and it’s very disappointing considering how much apple products cost. I’ve been an apple user since the first iPhone came out, and this is the first time I have ever considered switching to android or a different product. I’m beyond frustrated with the AirPods and the lack of response from apple.

For as far as I know that is not happening. Have you tried to reset the AirPods to see if the issues persist?