How did Sanju become an ATBB?

Leave aside Ranbir's excellent performance which was the heart and soul of the film, what is so special about Sanju?

I found it a flawed and badly-executed movie. It was an exercise in white-washing and pure propaganda. but even if we keep that aside, it wasn't a well-made film. It was jumbled and messy. The screenplay was average. The emotions were half-baked and not authentic. Too many characters ruin the flow of the movie.

So what was the reason behind its success?

movie was flawed and white washing a criminal. its RK who nailed the performance, making sure the goal of the director met. audience thronged theaters and wept. making it an ATBB