I think having the ability to sort the folders would help to manage those who have a large number of folders or add from time to time.
e.g. I am one of them.

Hi,
Although it seems like a pretty good idea, I think the process should be kept simple.
In my opinion, all that is needed is to sort only the subfolders/subdocuments/subitems from the corresponding selection. The reason is that I don't think that at some point and then the changes will be frequent.
Either way the decision is yours.
Thank you for the response.

As an additional option, it would be nice whenever you add a new (sub)folder/(sub)document/(sub)items to automatically sort based on the user's choice via the settings (ascending, descending or none).