AirPlay turned off and can't be turned on
The AirPlay icon in the menu bar is only shown when an AirPlay device is available, per the option ‘Show mirroring options in the menu bar when available’ (emphasis mine).

You're unable to change the option from Off because there are no AirPlay devices to choose from. There is no ‘On’ option ever, only a list of devices to choose, except there are no devices found so the list is empty.



There is never an AirPlay icon on the desktop.