No sound/microphone when making phone calls.

If you experience no audio across all options: primary mic, loudspeaker, ear speaker, secondary mic, tertiary mic, or Bluetooth; there is most likely damage present on the logic board. In my experience the issue is related to the audio IC which is the chip that controls these functions, or there is separation between the two layers of the logic board which can occur from drops or impact. In either case you will need a board level repair technician to repair these issues.