Microphone works with OnStar but not with Carplay or Bluetooth

I have a brand new (< 400 miles) Chevy Bolt and really like the car, but have an issue with using my phone and hoping others may have suggestions on how to resolve this.

Short version of the problem: when connected via either Bluetooth or Carplay and placing a call, I hear the other person clearly but they barely hear me, as if I were far from the microphone and there were a lot of background noise. But if I connect to OnStar by pressing the button, the OnStar advisor hears me loud and clear.

Consistent with the microphone issue: Siri rarely understands me and the "wavy line" barely moves (again, as if I am speaking from far away). This happens with both Bluetooth and Carplay.

I have reproduced the problem using a second iphone, so problem not unique to my phone. Again, problem happened both with Carplay and Bluetooth.

I have also tried unpairing the phone and re-pairing.

I checked software of MyLink and it reports that the software is current. I also tried holding down Home and FastForward for 10 seconds and the system appeared to restart. Problem persists.

Any thoughts on what else to try?

Is this a problem that the dealer can address? Never brought a car into a dealer with what might be a software issue, but there's always a first time.

Thanks for any suggestions!

I can only tell you from my experience that for some reason the bluetooth doesn't pick up the car microphone, but instead it is using the phone's microphone. Not sure why that happens. Try making the call using the phone when it is connected and speaking into the phone. For some reason on my phone that works. Not sure how to fix it, but getting the microphone to switch to the car seems to be what I run into.
So when you use OnStar it never has to do this switch. It appears to me to be a problem with the car's infotainment system as bluetooth headphones work perfectly. I do reboot the phone when this happens and sometimes that works. Rebooting the infotainment system doesn't seem to help this condition. What is weird is that the bluetooth is working for the dailing portion so why the microphone isn't switching is puzzling.

Thanks for the suggestion to speak into phone. I think I was doing that on at least some of the tests, but will try again. I am also going to reach out to Chevy Infotainment team.

Talking directly into the microphone on the phone does not work. When I talk right into where the mic is (above the mirror) the Infotainment person I was working with said that the sound got very fuzzy like the mic was overloading. So it seems like a mic issue. That would make sense if OnStar has a separate mic or a separate connection from the mic. Does anyone know if the other opening (passenger side) is supposed to be open as well? It is blocked by plastic.

Going into the dealer next week to have it looked at. I'll report back what I learn in case this is happening for other people.

Quick update: the dealer has determined that it is a bad communications module. Part on order. car went in on Tuesday and will get it back sometime next week. As I posted in a different thread, the module that controls the windshield wiper is also bad.

Thanks for this update.