This hasn't really been a problem on Windows for 99% of the applications for years now.

You can solve this problem really simply by just getting monitors that are actually large enough to use all the pixels and don't use scaling

What's the point of 4K if you don't use all the pixels?

Full disclosure my eyesight is terrible so maybe the rest of you can tell a difference between a high res screen that's scaled and a low res unscaled screen at the same apparent resolution.. but I can't

Doesn't Mac OS only do integer scaling? Is scaling to 250% or 300% an option? Day-to-day use I keep my Windows 13" laptop with a 3.5K screen at 300% scaling (nice and big), but for certain situations I will bump it down to 250% or 225% when I feel like I need more "space".