This happened for me as well, I have two DELL p2422HE monitors "chained" together, one monitor connected to the other monitor via displayport cable, and then connected to my macbook via one usb-c cable from the first monitor. This used to work perfectly, then I upgraded to monterrey and it no longer works. When I hold down the "option" button in the displays settings in system preferences I see the "detect monitors" button appears, but this does not work either, only one monitor is detected still.
enbecker
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