It's not "can you provide the screen DPI to a window?" people bemoan, it's "can you draw one window across two screens with differing DPIs, transparent to the application?"
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If so, good for you, but there are plenty of people who do so.
Hell, in X11 it even sucks if you use the screens one at a time, eg if you turn plug your laptop into the monitor and turn off the laptop screen, and then later unplug and continue your work on the laptop, the scaling will be off on at least one device.