Many mobile browsers already add this feature to get better experience. It is easier to reach URL bar, tabs, settings when the bar is at the bottom instead of the top.

2 years later

Here's hoping! Not sure why the option was removed in the first place.

a month later
a month later

Stephan-P chrome://flags/#android-bottom-toolbar (enable), restart Vanadium.
Then visit Settings > Address bar
and select Bottom

Buggy though unfortunately

Unfortunately, the bottom bar is overlapping the bottom part of the website.
Example: selecting suggested translations on the Crowdin website. The option "Use" is visible, the option "Use and save" is hidden.
Something is off with canvas rendering.