Can you provide temporary admin credentials, and we’ll have a look why it’s not working.
Side note: Page Hero – Block Elements are the more “current/modern” way of creating a Page Hero in GP. The Older way, which is the Header Element is more commonly used nowadays for just the merge feature. This is why I advised the Page Hero – Block Element.
In Appearance > Customize > Layout > Secondary Navigation, what’s the navigation location? Also, do you have a menu set already for the Secondary Nav in Appearance > Menus?