I think it’s a case of an unreliable narrator.
At times it feels we are seeing the camera girl’s feelings, and at times we are seeing her memories.
I think the simplest is that she ditched her besties for the boy, and in many ways that broke their friendship (her arm as a big symbol for his, she couldn’t dance / join them/ while she was with the guy, so she became their audience), her innocence lost (deer walking out, broken camera). The times she remembers as if it had all been made up, I think it’s her agony at losing her friends and tarnishing her memories of those times, maybe anger at them?
Then watching the tapes again as an adult it might mean she’s at peace with it but still yearning. Maybe I’m totally wrong ddd.
Not me analyzing this instead of working.