some mediocre (at best) movie.
I think there should be some sort of license people on the internet need to study for before they are authorised to use the phrase “At best”.
e.g. A film with a 90-93% score on RT from hundreds of thousands of people could be validly described as “Popular at best”, or “Crowd-pleasing at best” without fear of succumbing to hyperbole.
Perhaps “Some mediocre (IMO) movie.” would have worked better?