A post Endgame movie would have been nice, but they would need a drama to deal with rather than just being a doco about what they did back home. If you have any interest in the books the first two set immediately after their return tell a good tale.
When we see the crew in the future timeline it does make us want MORE..
Now that you mention it, a post-Endgame movie would have been fantastic! I doubt there would have been much demand for it outside of fan circles like our own, but hey, nothing wrong with making a movie just for the hardcore fans, right?