To be clear I am saying that drag and drop operations do not work during runtime. The designer literally does not work at all, for WinUI 3, for reasons that are

To be clear I am saying that drag and drop operations do not work during runtime. The designer literally does not work at all, for WinUI 3, for reasons that are not at all clear, since Visual Studio had a 'native' designer for WinUI 2, as well as the weird disconnect with Blend as you mentioned. I almost feel like you're mixing up WinUI 2 and 3, because the designer was kind of borky for WinUI 2 but did work, and was overall an okayish experience. But for WinUI 3 it's an entirely different game. Early on the messaging was that the designer would be "coming soon" (tm) and that people could just use hot reload in the interim, then at some point hot reload ended up completely broken as well, Microsoft gradually started withdrawing engagement with the community, and here I am saying it's been defacto abandoned. The point of the designer is not just mock ups. At many (most?) small businesses and studios the developer/designer dichotomy doesn't exist. There's a reason lots of companies are still even using e.g. Winforms. A high functioning designer simply dramatically improves both productivity and quality.