There are certain Android Apps known as 'gesture' apps, which enable you to attach phone functions to pre-defined, (or sometimes custom), gestures, globally. For example, you can set it so a left-swipe from the right edge will bring you to home screen, anytime. With these, there's no longer any need for nav bar. Currently, as far as I know, all of these apps require either root, or allowing permissions to access some Android service, (accessibility service, control touch input, etc), so, if you try to use them on Sailfish, you get an error, either 'failed to obtain root', if root is required, or 'this function is not available' if trying to get access to some service...