Bad, queit sound on AirPods 4 ANC

I used to have the usual AirPods (2nd Gen) and was completely pleased with that way how the sounded. Now, having bought the AirPods 4 ANC, I feel that there are not enough bass, the sound is flat and they are prety quiet in general (I need to set the volume level on ca. >80% when outside). I supposed that the problem could be also the new form-factor which just doesn't fit my ears, since the heads of AirPods 2 were much thiner and coulg go deeper inside the ear canal. However, I am not sure about that, because I feel no disconfort wearing the 4th AirPods. I have already tried out different settings and connected devices but nothing changes. Could someone suggest me something?