In mobile and tablet views, the categories off-canvas trigger is positioned near the top of the content page utilising/wasting a lot of view space. It would be better to move it lower, on the same horizontal as the inline mod trigger button. Screenshots ...
Side navigation collapsing is done in a standard way throughout XF, and that involves putting this button first and at an expected location (it's handled by PAGE_CONTAINER). So this is generally expected and not something currently controllable on a per page basis -- you'll see the same approach anywhere else there's a side nav; only the text of the button is something that can be changeable.