Microphone not working during speakerphone calls

Hi, i am having problem with my Google Pixel 4a phone, microphone does not work during speakerphone calls in: Messenger, Whatsapp, default caller app - my recipient does not hear me. When I switch to earpiece there is no problem - everything working fine. Audio is also recording fine both on recorder as well as when making video with camera.

I tried the factory reset, reflashing a phone, and also compressed air to both mics - top and bottom. I have even sent it to service - they have tried to switch top mic from another device however problem still persists. :(

I am living in Poland and it seems that Google Pixel 4a is not repairable neither in France or Germany, when I tring official Google support page.

Any idea what could I do more?