Honestly, Asus has some hit or miss customer service. I had flickering lines on my PG258Q. They sent me a new monitor. The new monitor developed a flickering as well. Second time they acted like I was a thief trying to take advantage of their RMA system. I even sent them a picture of the issue. Now, the warranty has passed and I am stuck with a flickering monitor. It's almost like they were trying to deny my RMA JUST because the warranty was a few months from expiring.
My monitor also has the occasional line down the middle issue. So did the original one that I bought.
Needless to say, I do not plan on buying ANYTHING from Asus in the future. I used to buy ALL of my motherboards and monitors from them. I even bought a 2080Ti from them... Yeah, I've thrown a lot of money at them over the years and now they are going to get ZERO in the future from me.