Flask is my go-to, but I've had great fun with Rust recently.

Django is the best thing in the world for writing Django apps. (No, I'm not trying to be funny there. If what you're doing looks like something Django would solve, it's fantastic.) But most of the things I do aren't Django apps, and ones you get off its happy path, you can be in for a world of hurt. Oh, you use SQLAlchemy everywhere else, and you'd like to use it in your Django app so that you can have one set of models and re-use the service logic you've built? Hah, too bad! Or you need your REST API output to look a very specific way? Have fun with that! Your auth model doesn't look just like Django's? Hope your LLM is good at smoothing that over!

The good side is that it's an opinionated framework that does a lot of research on your behalf and makes some great choices. The bad side is that you better agree with its opinions or you're in for a bad time.