DDC for brightness controlling a daisy-chained monitor

I have a Latitude 7430 with a U2722DE (integrated dockingstation) monitor and a S2721DS Monitor that is daisy chained to the U27. The S2721DS has DDC enabled in settings, but dell display manager has that option greyed out. Controlling the brightness of the U27 works just fine. I'm on the latest version of windows 11.