When I read the novel, some years ago but later in life, I couldn't escape the impression that the voice of Victor Frankenstein was the voice of Mary Shelley herself. The whole thing was just insanely Freudian. Don't get me going. So, fiction yeah, but it does have a grip on us.
Not into Freud, or psychology or anything like that, but the the Swedish (TV?) production of Frankenstein was the closest I have seen to the book, and rather different from the bits & pieces of the much earlier Hollywood production I've seen.
Don't kow where the "real" story is, but I don't think it's in the Hollywood version.