Had same issue, following some steps from a reddit back from last year.
Install Logi Tune from Logitech (https://www.logitech.com/en-au/video-collaboration/software/logi-tune-software.html)
Once installed make sure camera shows in the application > check to see if the camera is up to date through the Logi Tune
Go to Settings > Privacy > Microphone and disable the feature
Go to Device Manager and uninstall all camera devices for the C930e
these will be under
- Audio inputs and outputs
- Sound, Video and game controllers
- Universal Serial Bus Controllers
if you don't use any other Logi devices it is best to uninstall any logi devices from those three sections.
Once uninstalled unplug the camera and restart the computer
When the computer is back on go back to Settings > Privacy > Microphone and enable the feature again, make sure all applications are enabled.
Reconnect the camera then if you check in device manager under Audio inputs and outputs the camera microphone should appear now and if going to Settings > System > Sound you should be able to manage your sound settings.