DIAGNOSIS This is a temporary loss of signal synchronization. With USB-C, it's often related to the cable, power delivery negotiation, or a computer sleep setting interfering.
FIX Replace the USB-C cable. Use the one that came with the monitor or a certified high-bandwidth cable. Next, on your computer, go to Power & Sleep settings and set the 'Turn off display' and 'Put computer to sleep' timers to 'Never' as a test. If the blackouts stop, a system power state is causing the drop.
IF THAT DIDN'T WORK Update your graphics driver. Then, on the monitor, go to Menu > Display > Power Button and set 'Power Savings' to 'Off'. This feature can sometimes cause aggressive blanking.
HEADS UP If you are daisy-chaining a second monitor via the U2723QE's DisplayPort Out port, this can exacerbate signal stability issues. Test with only the primary monitor connected.