iPhone 13 Pro mic not working properly when using camera app….it is working fine with others apps like voice memo, FaceTime or whatsapp video recordings

When using my phone’s camera app, when I make a video, it sounds like I am in a car or by the ocean as my sound comes from very far away. However, sometimes the sound comes right back depending on the length of the video. This problem started just a little under a year after I got my phone. The problem was not that bad at that point and I didn’t make a ton of videos at that time to be too bothered. However with time, the problem has become worse and now I do make a bunch of videos. I was told that it is a rear mic issue that only applies to camera app videos. Given my phone is not under warranty….besides spending a lot of money for a repair, is there a way to just turn off the rear mic…..the iPhone 13 Pro already has three other mics and the video on other apps and voice memos are all working perfectly fine. I was told by one specialist that they could take care of me while the other said it is out of warranty and so I am out of luck. I have been with iPhone since the iPhone 3 came out and would appreciate a fix without having to spend a fortune for something like this.