I have a Dell XPS 13 9730 and I just bought a Dell S2721DGF monitor. It was working fine all day until I made the stupid mistake of trying to tinker around with the HDR settings - I was playing a game and wasn't impressed by the graphics so I thought that would improve it. Suddenly my settings changed and now I can only use the monitor as a Duplicate Monitor of my laptop (the way you would use a projector). When I try to set the monitor as my main display by clicking the "Show only on 2" option, the screen disappears for a second and then goes back to duplicate mode. When I try to make the monitor an extension of my laptop screen the monitor stops receiving a signal from the HDMI cable. I just spent three hours on live chat with Microsoft/Windows support to no avail, they tried everything from uninstalling and reinstalling drivers to messing around with the same settings that I did.

This is really frustrating, I'm really frustrated. I even tried to walk my steps backward and undo whatever I changed with the HDR but somehow I can't. I think it was fully off before but now I'm not even finding an option to turn it off. If anyone else has dealt with something similar please help, I'm really frustrated about this, I feel like it's such a stupid problem to have.