I was actually looking forward to this coming to iOS, but it’s one of the things that work great until they suddenly don’t. Back from a photo in Photos? Swipe down or top left corner. Hide the keyboard? Middle right. Back from someone’s profile in Messages? Swipe down or top right. Back from a PDF in Files? No swipes, just top right. Some of these do make sense if you follow closely how the UI elements fly onto the screen, but are confusing if you don’t.