How do I set expanded view while navigating?

The "expanded" view will not be displayed if you are already on the Map page.

It's this one I want to see instead of the map view during navigation.

Yes, I understand but, you will only get your desired screen if you are not on the dedicated map screen when coming to a turn.  

+1 for adding this capability to the navigation screen. (with an on/off toggle option)

It way easier to read and understand the zoom screen when driving complex routes compared to the standard navigation screen.

Especially the countdown to turn option is really efficient when exploring new routes