I have had very good luck with the folder structure out of the box.
App\Admin App\User
And if the admin or user has more than one role. But I kind of understand what you are looking at.
Large enterprise, i.e., Humana Military, Has separate logins and sections for Doctors vs patients.
But your folder structure would work, just namespace all correctly.
Are you using separate login tables for users and admins, or same table.
Users and admins seem kind of simple, a large company could even have an accounting department.
I have a situation where an admin can view account data, but only the bookkeeper can add, edit, delete.