Steam Overlay don’t shown when hold Shift+Tab.
When using Steam Big Picture mode, the overlay shown, but minimizes games (not intuitive if you’re far from keyboard and can’t press Alt+Tab to return to game. And some games bug when you Alt+Tab then).
I can’t do Alt+Tab on controller. I press Home button and game minimizes. I need to get up from the chair, walk to my keyboard, press Alt+Tab, get back to chair and back to game.