help me understand taxonomy

This is the structure I want to implement in the taxonomy, where levels 3 and 4 will be added by the user.

• 1 USA
• 1.1 SF
• 1.1.1 subdivision name 1
• 1.1.1.1 (team name 1)
• 1.1.1.2 (team name 2)
• 1.1.2 subdivision name 2
• 1.1.2.1 (team name 3)
• 1.1.2.2 (team name 4)
• 1.2 INFANTRY
• 1.2.1 subdivision name 3
• 1.2.1.1 (team name 5)
• 1.2.1.2 (team name 6)
• 1.2.2 subdivision name 4
• 1.2.2.1 (team name 7)
• 1.2.2.2 (team name 8)

If we create a dictionary with 4 levels, the question arises: how can we link fields when creating a content type to a specific node in the tree? For example, to "SF" and everything below it on level 1, only those that have "SF" as their parent. This means that only "subdivision name 1" and "subdivision name 2" should appear in the list.

When selecting "subdivision name 2," the list will include "(team name 3)" and "(team name 4)."

Now let's move on to creating the content type. I have 3 lists and an input field. How do I link them to the necessary LEVELS of a specific dictionary tree and make sure to select the appropriate parent at the specified level after the previous selection made by the user?

Alternatively, I could create different dictionaries for countries and subdivisions (but then I would need to somehow link specific subdivisions to countries), and so on. But I really don't want to do that.

PS Please don't be too harsh. I used search but couldn't find a solution for this specific task. 
"from now on there is a zero level" (c)