Hi Pedro,
I test it in my environment and I can see the hierarchiacl relationship on the territory entity normally.
Basically, you need to do two things, select Hierarchical to Yes, and fill the lookup field of the relationship on the territory entity form.
Please refer to my process to see if you have any omissions.
1) Open the relationship territory_parent_territory, change Hierarchical to Yes.

2) Go to Territory, select the Parent of the Territory.

3) Go to Territory view, wo can see the hierarchiacl relationship icon, click it, we will turn to the hierarchiacl relationship view.

If you create a new 1:N relationship for the territory entity, you still need to select Hierarchical to Yes, and populate the lookup field.

