I know that I can use ctrl+alt+shift+tab to go to the top panel. But I want to create a keyboard shortcut to trigger sections of it (for example the top-right menu in the panel). Is there any way for that?
Shortcut keys to open sections of the top panel include
Activities
Next to simply pressing Super, you can open the Activities overview with the shortcut keys Super+w or Alt+F1. There is also Super+a to immediately display the Application overview.
Application menu
The application menu, i.e. the button with the icon and name of your application, can be opened with Super+F10.
Calendar/notifications
Use Super+M or Super+V to open the calendar panel.
User menu
Somewhat surprising, no shortcut key is available by default to open the User menu at the right with the keyboard. Still, Gnome Shell can be controlled over dbus. Either of the following commands will pull down the User menu. Select one and bind it to a shortcut key using "Settings" - "Keyboards Shortcuts".
gdbus call -e -d org.gnome.Shell -o /org/gnome/Shell -m org.gnome.Shell.Eval string:'Main.panel.statusArea.aggregateMenu.menu.toggle();'
or
dbus-send --session --type=method_call --dest=org.gnome.Shell /org/gnome/Shell org.gnome.Shell.Eval string:'Main.panel.statusArea.aggregateMenu.menu.open();'
