I've just made a first project in fastAPI, and it was trivially simple compared to my previous adventures in DRF. Plus asyc from the get go, which was also pleasant. I had a task as part of this that takes 10 seconds to run, and there's a built in way to allow it to run in the background.
Yeah, at a past job I had to build out a way to run launchdarkly in FastAPI and it was very unpleasant. Launchdarkly only ships a sync python client so we ended up having to run it in another process to avoid blocking all requests
And the documentation is excellent.