Well, i must say i have never heard of the testing software you’ve used, but to me it appears to still be the microphone that seems to be the issue, the sending of your voice you’ve talked about is rather unlikely because you’d have issues sending everything, such as texts, something I encourage you to do is to clean your ports, theres one on the top, it looks like a bar next to your camera, and the ones on the bottom, next to your charging port, you can clean these using a firm paint brush or toothbrush.