<opinion>
Flask vs Django - Flask is a great project. It does a lot of things very well without getting in your way.
It’s almost an apples-to-oranges comparison. Django provides a lot of features that aren’t baked into Flask. As a result / side-effect of that fundamental difference, you have a lot more flexibility in Flask that is not easily available in Django. Which is important if that type of flexibility is important to you. To us, it’s not.
I got into this in a lot more detail in this thread, Should I use Django?, but the Reader’s Digest version is that over the past (almost) 5 years, we’ve migrated all our projects from Flask (and a couple other smaller projects in Bottle) to Django
</opinion>
Regarding our core project - we’ve hit the MVP milestone, but this is the type of project that is never “done”. The project it’s replacing was live and under active maintenance for about 10 years. (It’s one of those core-corporate type projects that can live forever.)