I don't have a left hand, I don't have six fingers, guess I'll stick with my mouse.
I'm sure this could be adapted for one-hand use, but- and maybe I'm slightly biased, but I think even if I still had two hands I'd prefer interfaces that don't require me to use both to do simple actions.
Whereas, I am able bodied, I'm also left-handed, which is annoying on a daily basis. Ignoring all the real-world issues, touch interfaces are optimised for right-handers. A 'flick' gesture for a right hand, is a 'push' gesture for a left hand, the amount of times a touch screen or touch-pad based OS mis-interprets my badly-done 'flicks' for 'push' and the screen scrolls instead of going back or forward. There are endless issues just like this, all because my finger-profile is mirrored compared to right-handers.
If Google enforce the 'pill' navigation on newer Android versions (right now it's an option), I'm going to have to seriously consider switching to iOS, as the 'pill' depends on right-handed 'flicks' to the left to 'Go Back'. Which for left-handers is a 'push' action, and won't be properly recognised.
Re: pill navigation- I find the navigation bar to be an outdated concept and I don't know why we even still have it at all. I use an app called "edge gestures" to navigate with swipes, and I disabe the system navigation bar. I suggest you try that.