(I've checked my backup stuff but don't fancy
Doing it at work). As i say, not just the phone mics, a Bluetooth headset mic doesn't work either.
on the old Nexus 5
the original one from years ago, you genuinely could mend some problems by tapping it on a table. Gently obviously.
it basically had rampack wobble, so the battery would wiggle a bit and interfere with the microphone.