Call quality and noise cancellation (regular calls, handsfree, Signal voice messages, Microsoft Teams video calls)

Help Fairphone 4
408

I also have callers frequently complaining about my voice quality, when I’m on hands-free.
I did the included checks

*#*#2886#*#*

and the one in the My FairPhone app. Both seem to be fine for the microphones.
Not sure where to continue now.