iPhone receiver Low Volume Problem

Apple replaced my iphone 11 in July since I encountered an issue of low volume in front receiver. I told them to revert to me with the reason because there was no physical damage to my phone and neither it was over expose to dust or water. And above all, this was not the first time I encounter this issue with Apple Phones. My older iPhone 6 also was replaced because of the same issue. So the issue is not uncommon. I am yet to hear from them on the reason for the problem. just wondering what should be my next step if I encounter this problem again? My iphone has just completed warranty period. Anyone else faced same issue and found the resolution?