I do use integer scaling. That's what makes 1080p bearable on my 4K display, and not other resolutions that don't divide evenly into 4K.
An annoying quirk is that I have to use the Nvidia control panel specifically to get Windows to send a 1080p signal as otherwise, it will just upscale 1080p to a 4K signal. It makes no fucking sense to me why that would be the default but whatever.
Can't you do the same thing in Windows' own Advanced Display Settings, by toggling the resolution in list of modes? (I might be remembering the naming wrong). That seems to work to change the "Active Signal Resolution" or whatever it is. But perhaps the Nvidia method is faster.
I agree that it's insane it works this way though.