for full screen to work in microsoft store applications, the condition is that the LWin must be held down, and then press LShift + Enter.
If you do all 3 at once it does not work.
Since the original Steam + menu shortcut presses the F11, which is a fullscreen mode, it is added that holding it down for a full second will call the microsoft store app shortcut in fullscreen.
for full screen to work in microsoft store applications, the condition is that the LWin must be held down, and then press LShift + Enter.
If you do all 3 at once it does not work.
Since the original Steam + menu shortcut presses the F11, which is a fullscreen mode, it is added that holding it down for a full second will call the microsoft store app shortcut in fullscreen.