You are talking about Win32 legacy API, stuck in Windows XP feature level.
Modern Windows desktop UI, UWP aka WinUI, uses C++17 with a framework called C++/WinRT, that hides those IInspectable COM interfaces.
Yes there used to exit C++/CX and Windows Runtime Library, both now considered legacy and replaced by C++/WinRT.
On modern Windows you have C++, and also layout DSL, specifically XAML. And that C++ is not particularly idiomatic, it’s IUnknown-derived interfaces.
If you mean windows desktop, WinAPI uses quite a few DSLs. Dialog and menu resources are the most obvious, but there’s more: WMF/EMF vector graphics format, ribbon markup XML for ribbon control, theme files…