Whenever I first heard about the "white savior" trope (a long time ago) it was very eye opening. Rather simple obvious concept that makes the centering of white people in stories which aren't really about white people, or at least where the stories would be better told with non-white protagonists, easy to see constantly.
Like the Bechdel Test, which shouldn't be called a "test" because the point isn't that a film should pass it, it's just a way of highlighting something. It's ok to have dude movies about dudes, to have movies that "fail" the test. The point is it shows how many movies, ones that aren't dude movies, still center the dudes.
I've long called him White Savior Nick and well....