Please note: It is not possible to add or delete default main categories.
So, you want to customise your main categories? Sure, why not. Here's how you do it:
You simply edit the category and use automatic rules - rename main/subcategories, but know the structure remembers the original categories due to machine learning and algorithms. So, you should use automatic rules to keep them categorised as you’d like them.
If you are an iOS user, you can use automatic rules via this web-app
Check here how to add, edit or hide subcategories.