@OOG Sadly this may not be resolved with an update as the majority of users have no problems. So to try and get to the root of your problem it would be useful to know some detail.
- Exact model of phone and build number
- What network are you using
- Does it happen when using wifi calling, what’sapp etc
- Can you record voice using the built in recording device
There are two microphones have you tried each in multiple apps
You can test the microphones individually
On the Fairphone 3 there are Service tests available via Settings - System - Advanced - Developer options (how to enable them in Android is all over the internet) - Service Menu - Service tests.
There are topics that are more directly related to your microphone issues in calls: