Device for general purpose augmentation - "ACUMA"? (GPT-3 invented the name)

I had an idea for a UI involving like a sort of window in midair that when you put your hand through it it adds like small labels over gestures you can use to interact with it and to use whatever app is controlling that window you just make hand gestures with your hand stuck through the window. But since the window only responds if your hand is in it, it wouldn’t get in the way or anything