Toggle stereo/mono audio (useful for when audio annoyingly plays only through one ear)

This can be accessed in Preferences. Just search 'mono', or go to Accessibility > Hearing > Audio.
This is useful when, for example a YouTube video's audio only plays through one ear. It's horrible. It sounds much better when you turn this option.
It's a bit annoying to navigate into Preferences to switch it on and off. It would be much easier if it were in Parallels Toolbox.