Sound Control includes the uninstaller. It can be found in the preferences.
Select “Uninstall Sound Control…” to begin the process. Be sure to restart your computer when finished.
If for some reason you need to download the Sound Control uninstaller separately you may download it here.
If you were using the System Extension on macOS 11 or later you may want to remove consent for macOS to load the Sound Control's plugin. You can find instructions on how to do this here: