There wasn’t really an aversion to or direct decision to not use Django, it just kind of naturally evolved. We were experimenting with FastAPI in some mock APIs used for test suites and some different projects and decided to incorporate it into a larger project.
The pulling in of other tools happened naturally over time. Perhaps we reinvented the wheel and Django may have saved some time or effort, but ultimately in the end we gained a very deep knowledge of the system we have and the things that make it work, and how those individual pieces might be usable in other projects/scenarios.
A large driver was honestly just that we had no organizational experience in Django, and so there was no one that even would have looked at it and said “Hey we’re just recreating what Django already does”.