As far as I know in modern Windozes all this ancient stuff - *especially* DirectDraw - are wrappers around something else.
Some of those operations probably use Direct3d 12 under the hood and obey the rules of double-buffering. As required by desktop composition in Windows Vista and up.

For example, (I'm using openGL) I noticed that when a transparent window was overlaying my window, the wglSwapBuffers call duration jumped dramatically. I could only conclude it's because the driver had to reroute the rendering output to desktop composition and was forced to wait for vsync.

Generally, such ancient technologies as DirectDraw or DirectSound are only supported to allow ancient applications run. Expect them to work but do not expect them work optimally.
I myself have one of goals to add support for Core Audio/WASAPI because while DirectSound 8 still works, it doesn't provide low-latency access to hardware buffers as it was doing in WinXP.