That is why I bought a coaxial USB-C to DP cable, i.e. shielded.Those random black screens are often caused by interference. Make sure the AC power cord is not near any of the data cables, that fixed it on my previous Dell monitor, just moving them apart.
Not having any issues on my current one (U2723QE).
@Dentifrice As I said before, go out and by a more expensive cable, your monitor is not faulty. One cable may work with one computer but not another. It is all about the signal cowing out of you computer, and they are not created equal.
Only then you will know if cable is at fault, but I bet 99% it is the cable.