You'll have to do a better job of expressing your concerns. 2 differences I have seen recently is that the VG279Q has an ips panel and built-in speakers.
I don't know the xbox, on the pc you have 144hz with the rog with displayport if the graka supports it....

Hey :=
Sorry a bit late but maybe it helps you anyway...

NO, the XBOX only has HDMI outputs, if you connect a monitor with HDMI 2.0, it can transmit a maximum of 120 hz. You can also get other monitors that are cheaper, and use the X-Box to the maximum, the XBOX will probably not be able to resolve 2K, or not to 120 Hz.

https://144hz-monitor.org/144hz-kabe...

You can find more information here :)