The Acer S277HK has a maximum contrast ratio of 100000000:1. That's over twenty times the contrast ratio of a 5000000:1 PC monitor, which is the most common contrast ratio.
A 100000000:1 dynamic contrast ratio is actually the best contrast ratio across all medium monitors that have been around for a similar time to the S277HK.
The worst contrast ratio amongst comparable types of PC screen is Mega Contrast.
Alternative PC monitors that have a 100000000:1 dynamic contrast ratio currently available which you might want to consider include the H277H ($269.99), or the G257HU ($213.99) both from Acer which is cheaper; or the Acer B286HK ($305.99) which has a better Rating.