I tried to use Windows on my laptop to run some ETL software, not because I was trying to get off of macOS but because that particular tool only exists on Windows for right now, and running it on a 4K display or a HiDPI display makes it completely unusable. The fonts for the icons and everything else are so unbelievably tiny and using the scaling features just makes everything bigger. If Windows had a good way of dealing with apps that aren't HiDPI aware, it wouldn't be an issue but even the tools that they do have aren't consistent in how they fix the issue. Scaling the UI by 200% isn't a good fix.

I tried switching to a Windows laptop at work a couple years ago, and bounced off of it (returning to an ancient MacBook) basically entirely because of this. That, in combination with the laptop's 4K monitor, conspired to make it impossible for me to read text in some applications I used without a magnifying glass.

I suspect that Windows might be totally fine with so many apps not being DPI aware if laptop manufacturers weren't also doing things like creating 15" 4K monitors.

This is something that Microsoft were highlighting to Win32 and WinForms developers long before HiDPI screens became commonplace. Unfortunately, it's only recently that the API support has been fleshed out. Compare Windows 10 (https://docs.microsoft.com/en-us/windows/win32/hidpi/high-dp...) with Windows XP to Windows 8.1 support (https://msdn.microsoft.com/en-us/windows/dn469266(v=vs.71)).