wp_get_nav_menu_items( string $menu, array $args = array() )Returns an array of menu items. $menu parameter is slug or id of Menu created in WordPress. $args is from here: get_posts, which isn’t very helpful for filtering what menu items you want to display. This function returns an array that you can display manually, but does not include any data about which menu item is active. Does include any classes set on menu items in $items->classes.
wp_nav_menu( array $args = array() )Displays a navigation menu. This function can be modified by passing a subclass of the walker class. Returns an unordered list containing all menu items with classes on the <li>s to determine active and active parent items.