Control an Apple LED Cinema Display from Macbook Air

Wondering if Apple Support's article (link below) can help:

If your external display is dark or low resolution - Apple Support

Eg: says:

"Check display brightness:

If your external display is dark, make sure that its brightness hasn't been turned down.

If your keyboard and external display are made by Apple, you can use the Brightness Up key  on the keyboard to increase brightness. Or choose Apple menu  > System Settings (or System Preferences), then click Displays and use the brightness control there".

Make sure the display's USB cable is connected to the computer.

Thank you for your reply, sverrewh,

and for giving us a little more info. on your needs.

Perhaps this answer given in an older (non-Apple) forum may help:

(Seems it was working for macOS Catalina, so may work on Ventura)

https://apple.stackexchange.com/questions/33360/how-can-i-adjust-additional-cinema-display-screens-brightness

Same issue. The brightness control is unadjustable. The USB connection from the LED Cinema Display is connected through a USB 3.0 hub.

Wondering if restarting your Mac (Apple menu > restart) will help.

ie: (deletes temporary files, may update recent setting changes, re-establishes connections, and much more).