With a quick glance, these seem like very different monitors. Did you not read the descriptions?
The 2K one has Full Array Local Dimming (FALD) and a FPGA chip with a fan on it. The other monitor does not have have FALD and has a much lower peak brightness so HDR if it even has it will be no good. Not only that, the more expensive monitor has a much bigger colour gamut. The cheap one only covers 90% DCI-P3, where as the expensive one is 97%.
What is it that you think G-Sync does by the way? If what you understand is it allows you to play without V-Sync and tearing then both monitors have this. One monitor however is more advanced than the other as I have shown above. These days there is no need for a chip in the monitor to have G-Sync, but it seems it is for HDR. I personally am not versed as to why this is. Maybe baddass can explain that to you.
If it was me, I would go for the cheaper of those two monitors unless HDR is a big thing for you. But paying 1K+ to have HDR that hardly any game will benefit from at the moment is a waste of money. Plus who wants to hear a fan whining in their monitor??
Hopefully you understand now
By the way, in the post you quoted in case you could not tell I was being sarcastic