The reason it's so complex is because of backwards compatibility. Non-DPI aware applications from before DPI settings were a thing can't advertise that they're not DPI aware, so if an application doesn't announce which it is, Windows has to assume that it's not aware. A couple years ago, Microsoft was able to make changes to the GDI libraries to automatically adjust the size of elements its rendering which makes a lot of things sharper. But things like images or anything on screen not rendered by GDI will not magically become sharp.