Update =Resolved = After completing troubleshooting, a DELL-Cares agent setup a part exchange.
Hello, I have bought 2 S2721DGF in Nov 2022, I am using one as a main monitor to my PC and another one as a 2-monitor setup for my MacBook Pro. The one connected to PC never gave me any trouble, while the one connected to MacBook Pro as a second monitor went black yesterday and does not show anything even if the power is on.  It has already happened before where I would be doing my work and the monitor goes to black screen which seem to be happening randomly. The moment it goes to black screen I see that there is a small flicker with color lines and it fades into black. I have seen multiple discussions on Dell forum and on other sites and I have tried to turn it off completely, disconnect all cables, push all the buttons and hold "power on/off" button for 8 seconds, 20 seconds, 30 seconds, a minute, then connect all the cables back and turn the monitor on. As "going black" happened about 5-6 times since I have bought it, this cold power cycle helped in all cases until yesterday. Now no matter what I do - it does not go back to displaying a screen. I am using DP and tried to connect it to HDMI, do power cycle multiple times with no luck. I have tried to connect it to my PC as a second monitor and reset it to factory setting through Dell Display Manager 2.0 - no success. I have tried different DP, HDMI, power cables, tried to connect it as a single monitor to a different power outlet and different PC even - it just does not want to work.  I would like to understand what are my options in this case?
S2721DGF, goes black screen and cannot reset