Hi @ROU13, let me see if I can help out here!
Have you been able to carry out a quick test of the microphones in the phone to see if the hardware works as intended? Find and tap Settings > Support > Xperia Tests > Speakers & microphones.
Another thing that you can try is to reboot your phone in safe mode to see if the microphone works better there. All apps downloaded from Play Store is temporarily deactivated while in safe mode and by doing this, you can see if this behaviour is caused by a downloaded app or not. For more information on safe mode and how to use it, click here.
Try this and feel free to keep me posted with the results!
