I’m using the latest version of WP and there is no admin bar to choose homepage settings.
I found it; had to exit Fullscreen and go to Customize under Appearance, although I still don’t have the Customize option on the top Admin bar.
In WordPress 5.4, the WordPress core team changed the default behavior of the Block Editor (Gutenberg) to open Posts and Pages in Fullscreen mode, instead of the previous default, which showed the toolbar across the top.
As you’ve discovered, you can change this view by selecting, “Top toolbar” from the drop-down menu in the top right-hand corner of the Editor.
You’ll still find the “Customize” link in the top toolbar when you’re viewing the front end of your site. And of course, you can always access it in the navigation menu on the left-hand side under the Appearance menu.
Hope this helps!