I agree that Windows 10 is better, but I would note that it’s only truly good for apps updated to the Windows 10 API (which differs from the Windows 8.1 one, which differed from 8.0), so I haven’t seen wide support outside whatever we’re calling UWP apps these days.
I don't use any "Windows App Store Apps" if that's what you mean by UWP apps (I did a lot of Windows desktop dev on WinForms, then some on WPF, but haven't kept up since then).
But everything I use seems to work just fine on Windows 10 across multiple monitors - Office, Visual Studio, Rider and a whole host of small applications (many old) that I doubt did anything specific to enable high DPI support.
UWP is the modern replacement for Win32, stuck in Windows XP cryogenic state, it is not only for the store since MSIX package format got released two years ago.
Now Win32 and UWP are just two complementary sandboxed execution models, more so when Windows 10X gets released.
