Good morning, David.
The reason you didn’t see the button when you looked is that I had the mobile menu breakpoint and navigation drop point adjusted so the hamburger menu would show on all sizes.
I have a Block Hook created and set to menu_bar_items. It did add the logout button. However, a duplicate menu item from my primary menu is right next to it, not styled as a button. I don’t know how to get rid of it. When I deleted everything out of primary navigation menu, every page on my site showed up there.
I prefer to have both the button and the hamburger menu in the site header, along with my site logo, but will settle with having one or the other.