The Dell S2722DC is a 27", 2560x1440 pixel monitor.
Once upon a time, Mac OS X / macOS did something called "sub-pixel anti-aliasing" to improve the appearance of text on monitors with regular PPIs (like 24" 1920x1080 and 27" 2560x1440 ones). My understanding is that Apple removed support for that feature several versions of macOS ago. As a result, text on a 27" 2560x1440 monitor like that one might not look as good as it would have looked under, say, High Sierra.
27" Retina 5K iMacs did not need to use sub-pixel anti-aliasing on their built-in displays, because their pixels were small enough to draw letter shapes (more) accurately without that trick. Alas, Apple has discontinued those iMacs, and the 27" Apple 5K Studio Display + an Apple keyboard and mouse might set you back as much as an entire 27" 5K Retina iMac (that included the computer) used to cost.
These days, if you don't have the budget for a 27" 5K monitor, it's probably better to get a 27" UHD 4K monitor and run it in Retina "UI looks like 2560x1440" mode than to get an actual 27" 2560x1440 monitor.
There are a few photographers who may insist that they cannot do their pixel peeping at anything other than some exact setting - e.g. 5120x1440 or "like 2560x1440" for a 5K monitor; 3840x2160 or "like 1920x1080" for a 4K one. But at a "like 2560x1440" setting, a 27" 4K monitor would give you better text than an actual 2560x1440 monitor – the Mac would use the extra pixels to draw letter shapes in more detail. And you would have the option of making the text larger ("like 1920x1080" – but with Retina detail) if you needed oversized text.
