Yes, without scaling everything would be way too small to read. And yes, this is the main reason why there isn't many 24" 4K monitors, even on 27" monitor you'd have to scale it.
Windows does have a setting for scaling, but it's not always perfect so some things might be blurry etc. And depending on how much you scale, you don't get much more space on screen than on a 1080p (or 1440p) monitor.