I find the button to be confusing. Most people's home button/function is in the center-bottom of their device. Top right button is typically an X to get out of something.
Discussion
Most smartphones no longer have a home button. Instead, users swipe up from the bottom edge to exit apps and return to the home screen — and this gesture is reserved by the system. That leaves us with only two options: placing it in the top right corner or at the center bottom. But putting it at the center bottom would block part of the screen content.
Perhaps we should try placing it at the center bottom and see how it feels.
On graphene, in Settings>System>Gestures>Navigation mode, I currently have 3-button navigation selected instead of the default Gesture navigation. Might eventually switch back, but for now I like the more deterministic?/predictable? feel. May be very few that choose this, but just wanted to input at least one reference point in case it might play some part in your UI decisions. Thank you for your app!