How to show menu bar in macOS with keyboard shortcut
System Prefs > Keyboard > Shortcuts > Keyboard
Move focus to the Menu Bar [default Ctrl ⌃ F2 ]
If you wish, you can then navigate the menu with the arrow keys - but it will pop the menu bar into view; Esc to close it without further interaction.
If the standard
Ctrl⌃ + F2
does not work try
Ctrl⌃ + F2 + FN