I also started having this problem yesterday all of a sudden. My setup is this: Macbook pro m1 max 14" Monterey 12.2 LG 38**95C-W monitor (https://www.lg.com/us/monitors/lg-38**95c-w-ultrawide-monitor) Connected my macbook to the monitor via usb-c to usb-c cable (= thunderbolt connection on the monitor) This cable also charged my macbook This has worked without any problem since I got the laptop in november. Yesterday it stopped working. I have tried a lot of things mentioned in this thread but nothing worked for me. I have as a quick fix replaced my thunderbolt cable connection with a DisplayPort (from the monitor) to usb-c cable (connected to my macbook). This works but it also means I need to connect the apple magsafe cable to charge the macbook. Please apple, fix this!