I had no idea this film existed, but you've piqued my curiosity, especially about the mix of formats you mentioned. The concept of using real footage and outtakes from decades ago to construct a new narrative is fascinating; it sounds like a super risky experiment, but from what you've said, it works incredibly well to portray the passage of time.
I'm definitely adding it to my list. Thanks for the discovery because it sounds like one of those films that feels very alive and personal.
Check out Ash Is Purest White too, from the same director. Also Black Coal, Thin Ice. Another great one but from a different director