What is Donnie Darko about?

A question apparently asked all the time but unlike most audiences, I actually understand Donnie Darko perfectly. It's about um- a guy...

Ok listen I know the messages get a little bit muddy but I wanted to come out as someone who recently watched Donnie Darko for the first time without hearing much about it ever and try to give my own explanation just based on the actual content of the film before I look online for the accepted answer like everyone seems to have about Joker or Fight Club like does everything need to be explained? I honestly think that creators should just shut up after the movie is out, I don't want to know more about what you think. The story is out in the world it is my turn to take my meaning from it

So Donnie Darko. First let's start with the basics. Donnie Darko is the story about a guy who "escapes" death. Now I say this ironically because I don't believe he actually escapes. It's not like he's saved from dying or he saw it in a vision or anything like in Final Destination. He simply went out for a bike ride like it is said that he does most nights (something his mother is upset about at the start of the movie) and because he was out of the house he misses being hit by a piece of a plane that falls directly onto his bedroom and does not harm anyone else in the house (and does not harm the house enough for it to be a problem for the rest of the month that the movie takes place in?). Anyways after this brush with death he starts seeing a new figure in his mind? I don't know what the exact terms are to talk about psychosis but it is also established that this kind of stuff has happened to him before. In the first scene with his family his sister talks about how he's on medication because he's crazy and in many later scenes we see him and his therapist. When Donnie first mentions Frank his therapist already knows to ask whether he is real or imaginary and Donnie is not offended by this question, so he has had these problems and people have known about them for a while.

Getting back to the point, Frank is a man dressed in a bunny suit that Donnie sees, talks to, and takes orders from for the whole movie. Frank is the first point of contention that my brain keeps going back to. Eventually, it is revealed that Frank is not just an effect of psychosis but the spirit of a man who Donnie kills at the end of the movie. But then this poses some questions. If Donnie shoots Frank because Frank "made him do it" (trash his school, commit arson, the third crime I'm forgetting) then doesn't Frank make him do it because he got shot. At least that's what I gathered from the cinema scene and Frank's vague lines and face reveal.

Now all of this might make you believe the story is simply caught in some kind of non-linear time structure, not non-linear storytelling like the common writing technique but non-linear time itself, at least that's what I thought. But the ending of this movie does not fit into the non-linear structure I was picturing. So something about Donnie's actions, or maybe it's just fate, creates a wormhole above his house in the end, after his sister has fallen asleep and while no one else is in his house. This might actually be a result of him shooting Frank I honestly can't remember but the important thing is that Donnie's girlfriend Gretchen has been run over by a car because of a long chain of events and Donnie, he seems very affected but in the weirdest way. Donnie puts Gretchen's body into his car as if she is just sleeping and drives up to the top of a clif overlooking the town and sits on his car and laughs. His mom and his little sister are in the very plane that crashed into his room at the start of the movie and he is sitting at the top of the cliff watching them crash because of the worm hole tornado that's formed and he's laughing. And then it all shifts.

Suddenly, we are back in Donnie's room at the start but he is there. He is in the room when the plane part crashes in but still, the part of the plane came from the plane that his mom was on on October 30. It had to. It cannot be explained away by "it was just a dream" as was my first thought but it also can't just be the alternate universe... or can it?