Setting new menu items not working using Velo

So I see in a previous forum post that it can be due to the number of nested submenus. When I removed a submenu level, adding a new item worked. However, now I would like to ask:

The API says that if you set a menu as advanced, you can have two additional submenus? (Not sure if I’m understanding correctly)

I’m on the newest type of menu (with dropdowns). How do I do this?