Display of OSDs should not inhibit keyboard shortcuts
There are several conditions, especially under Xorg (GTK2 toolbar menus, GTK4 popovers being shown, etc.) that prevent the GNOME OSDs from being displayed. This, however, means that the associated actions (e.g. muting sound, or changing display brightness through hotkeys) are being also ignored.
Instead, the actions bound to the OSD/hotkeys/whatever event (e.g. changing volume) should be carried out even if the OSD cannot be shown. What is unknown, however, is whether Xorg even allows key-grabbing (and thus event handling) by Shell in these cases.