When I was designing a local tool for myself earlier this year I used navigation at the bottom and right side of the tool. Even though I am the only one using it, there's also a small button on the left to swap to left hand mode.
Using this tool has proved to me that the nav(on mobile) belongs on the bottom and/or lower half right with a left hand switch.
I agree, but for this specific case we have to discuss if the UI of a mobile browser is the browser itself or the content/page you are on. I'd argue that prime screen real estate should belong to the page, I don't use a browser to use a browser but to view and interact with content. On my iDevices I set Safari to using a top bar. Sadly the new default of the bottom bar and the large active area used for swipe up detection (on all devices since the physical home button was removed) makes the bottom of the screen barely usable for UI often requiring scrolling further down to dismiss the URL bar or tapping buttons twice, devs know this and hardly ever build UI utilizing the bottom of the screen, the most easily accessible part of the device for most users.