Python also has a range of Async web frameworks, which have equal or better performance than their JavaScript counterparts like FastAPI.

Where tasks are not CPU bound (as stated by another commentator) this makes sense.

The other key aspect missing here is the actual front end interface. What's the user experience if a user clicks a link or button and needs a page refresh to see the data?

Or out another way, the front end needs to support Async of some form either by hand written JavaScript, a framework that supports Ajax (e.g. jQuery) or a JavaScript frontend framework like React.