I use FastAPI exactly because of the reasons you point out... but damn do I miss the Django ORM and admin. Django-Ninja is an acknowledgement of the realities of that.
Having heard of Django-Ninja before. Looks really good! If I understand correctly it would allow me to keep the best parts of Django (ORM, Admin UI) and build a FastAPI-inspired API? That’s an awesome combo! Curious to see benchmarks how it compares to ExpressJS.