That way of boiling down Finding Nemo seems to miss why the story is designed that way. It doesn’t describe anything about what happens to Marlin as a character, just a few basic plot points, and then in the end he somehow learns that “love depends on trust”. Uh, ok.

If you actually want to understand why Finding Nemo “consistently tugs at heartstrings worldwide”, Craig Mazin used it as his primary example in “How to write a movie”, episode 403 of Scriptnotes[1]. (TL;DR: the purpose of everything that happens in a movie is to expose the hero to as much agony as possible, so that the change they’re forced to go through feels real. I don’t know what that means for your startup pitch, though.)

1: https://johnaugust.com/2019/scriptnotes-ep-403-how-to-write-...