How to customize forms and data in Django admin?

Question

Django

I am developing a project in which 90% of the site's work is tied to the admin panel. Those. on the front, only 1 page shows the result (selection from the database) of a specific query.
My question is this: how to write logic (view) for the admin panel in Django. For example, to create some kind of record, I have to click on different radio / check / select elements in which various checks are made, while they are loaded via AJAX, plus it has its own templates. In general, I need a full custom for the admin part, which I do not get when registering a model in admin.py normally.
What is the best way to do it?
Is it right to write your own admin part, in which access will be only for a specific user, and then I can safely screw my views there without digging into the native Django admin panel?
This is the first time I've come across such a problem, tell me who already has a similar experience. Thanks in advance!