How to create nested publications (publications in a publication) in WordPress?


I would like to create the two individual posts (which are essentially articles) and category posts (which are listed as posts, but also have posts under them).

The idea is: a Travel blog with messages in messages.

Some messages are whole trips (with several posts under them), others are just simple articles.
All are directly posted in the main category (say "my travels").

The trips would look different with a different button.

But, essentially, they would all look like publications.
When you click on a travel post, you will find more individual messages under their name or … sometimes you can find more trips and another level below the individual articles.

Let me list an example of the structure:

"Summer trip to Spain" [trip]
> "Travel in Catalonia" [trip]

>> "The best places to visit in Catalonia" [article]
>> "What is Catalonia famous for?" [article]
>> "The best museums to visit in Catalonia" [article]
> "Explore Madrid" [trip]
>> "The cultural heritage of Madrid" [article]
>> "Madrid street pictures" [article]
> "Visit Valencia" [trip]
>> "The most beautiful beaches of Valencia" [article]
>> "The old city of Valencia" [article]

"The best American airlines" [article]

"My favorite airports" [article]

"Visit Cuba" [trip]
> "Experience in Havana" [trip]
>> "The magical streets of Havana – Photo Gallery" [article]
>> "What to do and what not to do in Havana" [article]
>> "The cultural heritage of Havana" [article]
> "The best beaches in Cuba" [article]

"The big European cities to visit in 2019" [article]

Basically, some are nested under each other, but I never want to go down more than 3 levels. 3 is maximum.

I will make sure to distinguish TRIP from ARTICLE by design. They will look differently.

I've intended to use Elementor to create a WordPress theme, but I have not found a way to "nest" publications under each other.

How can I achieve this goal?