With the latest firmware updates and Your Phone update it seems the call quality is better... except now I can't talk to anyone. They can hear me but I cannot hear them.
One step forward, one step back.
I have the exact same issue. The calls are indiscernible. Like people are talking through a spring or something. It's really disappointing.
I am on Windows 10 Fast Ring, Your Phone 1.20041.88.0, and a Google Pixel 4XL.