XV273K is a pretty bad monitor. Fairly poor response times in the grey to dark grey transitions, in addition to poor backlight uniformity on left and right edges. Dual cables also loses you Freesync.
I would not recommend the monitor at all.
The XB273K also has the same panel lottery issues but at least the overdrive is fixed so it doesn't hovering around 9ms in grey to grey.
Honestly I wouldn't go with either since the XV273K is bad and the XB273K is a half measure. X27 if you want HFR 4K at 27" or go for something else entirely.