I believe you can remap the keys for navigation in the preferences (arrows per default)
in hotkeys I have up / down arrows assigned to DVD navigation ( a default setting ? ) , but I also have them assigned to fullscreen on / off. & the latter takes precedence always. I want to only use keys that I can emulate on my remote so I have limited options. if there was a full screen toggle option that would reduce number of keys neede by one, but I don't think there is ( except as a bug in 1.1.0 where up arrow is currently togglingthe fullscreen and preforming as per its hot key definition )
I find that different DVDs use different navigtgion techniques within menus e.g. in some you need to moew to a next or a nome button to progress, in some arty/trendy onee you have to hover over & click a particular screen area - easy with a mouse, hard without.
one program that copes consistently well is Powerdvd ( + it's own remote), but it lacks some of my favourite VLC features! Zoomplayer does not work well - it tries to sense when it's in DVD mode & swtch key assignments but I struggele to get it to work consistently.
the vlc hotkey for return to DVD menu does not always get things right. IN powerdvd there's the notion of title menu & root menu. , and the menu key on their remote seems to chosse the right one everytime. But vlc will sometimes only return to title menu so you can't escape to other sections of the DVD, just via keyboard