Increase number of navigation on the Header to 5 or 6 in the pro version

The default number of navigation on the Header is 4 in pro version. But sometimes if I have multi-level subcategories for WooCommerce sites, I want to make the category in a separate menu as I want to make it in mega menu. Currently the mega menu is only allowed for parent menus, if I need to make submenu item in mega menu, then I will need more menu, so more navigation in the headed is needed.