Looking at the Main Functions settings, The Audio (Audio Scene) is disabled and it doesn't appear to be able to be modified. The camera is currently in the Auto Mode and the Mic input doesn't appear to allow the standard 3.5 plug to be able be fully inserted anymore
The audio scene option in the menu is specifically designed for the built-in microphone, so disconnect any audio accessories you have and then try again.
If problems persist, try using a different mode like P.
As to using an external microphone, make sure that it is self-powered (with a fresh battery if applicable) and that the cable does not appear frayed or bent.
If problems persist, please elaborate on what happens when you try those suggestions.
I don't usually use a microphone, and instead use the output of the sound source (audio out).
Per my initial submission, I noticed that the microphone (or audio in cables) 3.5 plug no longer goes all the way into the associated port. It's almost as if the receptacle where the 3.5 plug goes in is broken inside. I get the feeling that I may have to have a tech person open up the camcorder to see what is going on.
It turns out that part of the 3.5 mm Microphone (or Audio Input) plug broke off inside the camcorder's associated port. Once I had a repair person remove the broken off piece of the plug things appeared to start working in the area of audio input. I'm still wondering why the "Audio Scene" and "Volume" configurations are still greyed out under the settings configurations user interfaces.
09/26/2023: New firmware updates are available.
08/18/2023: Canon EOS R5 C training series is released.
07/31/2023: New firmware updates are available.
05/31/2023: New firmware updates are available.
05/18/2023: New firmware updates are available.
03/30/2023: New firmware updates are available.