It's pretty funny how i went into this film without knowing anything about it, right after watching Pain & Glory by Pedro Almodovar just the day before and they ended up following pretty much the same structure: two timelines, in the present one you see the main character (loosely based on the real life writer of the movie) deal with the trauma of past events that get shown to you in the flashbacks, and deciding, in the end, to write a film about his life story that ends up being the one you basically just watched, creating a fun inception kind of feeling. Almodovar takes it a step further by showing us the flashbacks were a movie set all along, and LaBeouf does it by being the one that plays the role of his father.

They're both great films that, through the juxtaposition of timelines, successfully encapsulate a person's whole life through making the past a constant in the present and delivering the message that all of us are just collections of moments, feelings and events, all happening at the same time, regardless of time or space. It's a really interesting concept, that does a terrific job of building iconic leading characters.

EDIT: both Little Women and The Last Black Man in San Francisco also self reference their own stories in similar ways. 4 movies from 2019 about creators that end up creating the story you're watching.