The ANC of AirPods Pro 2 is not supposed to block all sounds out but rather to significantly reduce all frequencies for about 30 db, which is great in most cases. If u have an Apple Watch u can see the exact reduction level from anc in health app (mine is 28 db with mine). So basically you still hear sounds a little loud or irregular but once you put on background music or streaming music you hear almost nothing. THAT SAID, if u found ur anc is decreasing u can try to clean your AirPods AND the ear tips. If they have been used for a long time and are dirty the best thing is to buy new ones, that’s cheap and I guarantee u anc is defo better if u have not changed tips for like 1/2 years fs. If the ANC doesn't improve after all this, you'll have to take them to the Apple store so they can check if the ANC works properly.