How to show the 3rd & 4th level of post category

Hi, I have four levels of categories for Posts, something like that:
Country
– Region
— City
— Street

Country appears in the home page as the main menu, but it shows only the region menu
I’ve read this article on your website:
https://taxopress.com/how-many-levels-sub-categories/
but I could’nt apply it on my website.
is that possible?
Thanks