Bluetooth connection problems /airpods

Hello,

I'm having problems with connections between aipods 2 and to my iPhone 11. Connection with them works normally, but when I'm in the subway or in places where there is a high concentration of people, the sound first starts hoarse, stuck , like an old internet modem and the song either gets paused or continues depending on the situation and thats really annoying. But when I'm alone at home, for example, the AirPods play well and without disruption and there are no problems with them. I tried connecting the headphones to the apple watch and they don't have the problem. Apple watch connection seems to be fine. In the system, the buttom is normally blue and I didnt get any notifications about unavailability of bluetooth. Don't know what it could be? I recently changed the lightning port part and the entire back frame of the phone, but I started noticing problems only after the ios18 update. I checked the Bluetooth Antenna for the rear camera, it should be connected well, but it will probably need to be replaced as well. Do you know if there is a possibility that the error is somewhere other than the antenna before I order it? Of course, I disconnected the airpods, unpaired them and added them without any changes.

Thanks for answers!