If you use non-Apple branded monitors with your Mac, I highly suggest the free utility MonitorControl. It simply allows you to use the native keyboard buttons to control sound and brightness for external displays (even if you have more than 2).
If you use non-Apple branded monitors with your Mac, I highly suggest the free utility MonitorControl. It simply allows you to use the native keyboard buttons to control sound and brightness for external displays (even if you have more than 2).