Should I learn FastAPI? Why? Doesn’t Django or Flask do the trick?

I’ve been building Python web apps and always used Django or Flask because they felt reliable and well-established. Recently, I stumbled on davia ai — a tool built on FastAPI that I really wanted to try. But to get the most out of it, I realized I needed to learn FastAPI first. Now I’m wondering if it’s worth the switch. If so, what teaching materials do you recommend?