Hi
I have also been working with Django for many, many years. All of our apps have been based around the many features/options already built-in to the admin and it works perfectly "as is". There is really a lot you can do with it if your users are accustomed to working with more traditional grid-like database apps (and/or spreadsheets). For reporting you need to write your own code but its easy to add this in. Adding "logic" to do data checks and make more complex changes is possible via actions. The main advantage of the admin is that you're not writing a whole lot of code that you then have to support!
If your users want a more "modern" front-end e.g. a Single Page App, then yes, you will use Django simply for its ORM-modelling, add the Django Rest Framework on top, and then develop your front-end using whatever JS framework seems most popular these days.
My 2c
Derek