Although I haven’t used these monitors, my experience with high dpi on windows and Linux has been a nightmare compared to OSX. It’s surprising me the non Mac world hasn’t made this a bigger priority.
I genuinely have zero idea what you are talking about. Typing this from my macbook connected to a 5k LG ultrawide monitor, and it is as crystal sharp as it can get. As opposed to my windows 10 desktop (connected to the same monitor) having some occasional application windows render fairly blurry and inconsistently (one of the main offenders of this is, ironically, task manager). And don't even get me started on font rendering in general.
Windows does a Much better job with non-integer scaling because hairlines are 1px no matter what the scaling and text is rendered with pixel-hinting instead of macOS's new, lame strategy of super sampling.
For me, I only closed the book on the issue after finding BetterDisplay [0]. Basically a 3rd party program that gives you complete control over resolution, display density, and a ton of other options on MacOS. It has a trial mode but it is well well worth the money. With that + the CLI tweak to set font smoothing to 0, the 4K experience on MacOS looks decent. You can even decrease the effective scale of the native screen past "More Space", so those of us with good eyes can actually take advantage of the screen real estate.
Also, if you're curious to explore this issue beyond my subjective thoughts here, these [1] [2] blog posts do a great job diving into what is so bad about MacOS scaling, why 4K 27" or 32" screens end up looking bad, and why 5K 27" look okay.
[0] https://github.com/waydabber/BetterDisplay
Most people (and companies) aren't willing to spend $1600 on Apple's 5K monitor, so they get a good 27" UHD monitor instead, and they soon realize macOS either gives you pixel perfect rendering at a 2x scale factor which corresponds to a ridiculously small 1920x1080 viewport, or a blurry 2560x1440 equivalent.
Are you sure you aren’t confusing Window’s terrible font rendering with sharpness?
This is particularly frustrating since I've been using high DPI displays since the CRT days. Everything horribly regressed about a decade ago, and still isn't back to 1999 standards.
Where things go haywire is mixed resolution. It's best avoided :-\ Hence now I have a 28" 4k external screen which is exactly like four 14" FHD screens of my laptop, so the DPI stays strictly the same.
I did the same and just bought monitors that all have the same DPI, so I can easily use scaling that matches on all of them.