DirectDraw is an incredibly simple API (it doesn't even have 2D primitives - just blitting rectangles of pixels from one surface to another). AFAIK the fallback is basically doing that in software - since this is plenty fast these days - and letting the compositor handle the actual screen update. There's no reason why this would result in 30 FPS even on 20-year-old hardware, and indeed I regularly play a DirectDraw game from 1999 on Win11 without such issues.