I understand the feeling about the many menus lol. The Polygon display options are under the "Display" menu, which is in the main menu set between "Create" and "Window", can't miss it. Display>Polygons and "custom polygon display" options near the bottom give you access to all of same items in the menu plus extra stuff, so pick your poison.

Smooth/Flat shade modes can be found under the "Shading " menu at the top of your 3D workspace panels.