27" 4k would require about 125% scaling. And scaling atm is still shit. Especially fractional scaling like 125% (5/4). This goes for any OS.
27" 1080p is just shit tbh.
What about buying two 21-23" 1440p monitors? I don't know how much vertical space you need, but this gives you 89% pixels of the single 4k monitor. And if you take into account you'd have to scale the 4k monitor by 125% anyway, you end up with 11% more effective screen space without all the scaling issues.
Single 4k monitor would be comfy at 32-34". By "comfy" I mean using it the whole day without your eyes getting tired.