a story is a narrative construct. it doesn't need any particular structure. I mean, yeah in writing 101 class they tell you it needs all sorts of things, but writing 101 is a vast oversimplification of the diversity of stories and narratives that are possible and exist. I read plenty of books and watch films that have no clear linear narrative, and some of which the point of the movie/film is that such narratives themselves are suspect, oftentimes in the effort to reflect or explore the non-linearity of human consciousness. You seem to think only the writing 101 definition is the only legitimate way to think of things and claiming everything that isn't neat and tidy.
Just because my writing teacher demands a particular story structure, doesn't mean that's the only type of structure that is valid. It's juts the one that's valid for getting a good grade in her class. When you start reading stuff at more advanced levels the 'rules' you are taught typically no longer apply or are optional. That's true of a lot of things. And some of my teachers think I'm a major asshole for talking about things that don't fit into the neat little writing 101 formula.
Yeah it's totally OK to only watch a portion of it. When I wrote papers for film class I typically focused on one scene or segment and watched in dozens of times and wrote specifically about that. That's what film class is. You watch the movie as a whole, then break it down into components and learn how they function, and work together. You also figure out what may be problematic and identify the influences, target audience, and lots of other things.
My mom has dementia. Linearity no longer exists for her. Her memories are all jumbled and she conflates the past with the present and has no sense of time or identity anymore. I read a book called Wittgenstein's Mistress that is about a person with dementia. The book has no story in the conventional sense. It is a first person story about someone who keeps reliving their memories and can't make new ones and the repeated memories keep changing and distorting. It was incredibly powerful because it helped me understand and empathize with what is going on inside my mother's brain. I'm sure for you such a novel would be a confusing piece of shit that made zero sense. It has no plot, no storyline, no conclusions, and arguable, no characters. Yet it still tells a clear and distinct story about a person.