another way of looking at this is examining how much context a user needs to understand what effect a gesture will have, and how effectively that context is being communicated. Can i write a step for step guide to doing a task on a computer, for a computer novice, that doesn’t include first determining where in the operating system you are, whether the correct application is open, figuring out which of many methods can get you into that apllication are applicable in that situation?
no.
this is what was nice about the “home” button on iphones: it doesn’t matter where you are in the system, there’s a physical hardware clicky button that will always bring you back to the start, and cannot be overriden by third party software.
apple ruined it with the iphone X swipey home gesture. not only is it hidden interface, but it’s modal now-which edge you swipe depends on the orientation sensor, and is —- sometimes but not always visually indicated by a line that is maybe correct.