I don't have a touchbar mac to test, but does it work with external non-apple displays? Via Karabiner you can configure keys to change the external display brightness. Works great on a Thunderbolt Display. Completely ignores my Dell / LG.
The main reason why I think this wouldn't work is because in the display properties there's no brightness slider for non Apple external displays. There is one for Apple displays.
The main reason why I think this wouldn't work is because in the display properties there's no brightness slider for non Apple external displays. There is one for Apple displays.