I don't know for sure that this is the one that I watched, but I think so and the time frame is about right: [The Inside Story](https://www.imdb.com/title/tt1918873/).

The deep details of the movie are fascinating. Schlock filmmaker gets a recent Oscar winner and an experienced but little-known in Hollywood actor to take on a very confusing story, which then debuts into a slow burn that gradually builds over more than a month to become one of the best movies ever? You would never sell that as a script because nobody would believe it, but it really is true.