Internal mic not working on voice calls (Pixel 3a)

I can hear the other person but they can't hear me.

But when I set the phone to loud speaker or put in an earphone, the other end can hear me.

I've tried the following to troubleshoot but the issue still persists:

- Boot to safe mode

- Fully update OS and apps

- Mic works when recording video

- Mic works for audio recording

I need some advice before having to get this for repair. RMA is not an option for me since I got this phone via an import seller.

I have never dropped not gotten the phone wet.