Do you mean force-shrink the menu hamburger at certain story moments (f.e. CGs)? quick_menu_is_open is a newly added Ren'Py variable, so you should be able to easily control its value in Ren'Py scripts where you want it to happen.
Force shrink hamburger:
$ quick_menu_is_open = False
Force open hamburger:
$ quick_menu_is_open = True
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Or if you mean hiding everything that has to do with quick menu buttons.
The big button's visibility is controlled by the quick_menu variable (I kept the same name as Ren'Py's default), and right now the 6 quick buttons are separate from this. This is my first project and it's been ages, but I've now rechecked and notice that it is a bit of oversight to not write the following check in screen quick_buttons() in the following way:
if quick_menu_is_open and quick_menu:
By applying this change, then you can use these following statements.
Force hide quick buttons:
$ quick_menu = False
Force show quick buttons:
$ quick_menu = True