> the movie is really about the negatives of extreme, prolonged toxic masculinity
Chuck Palahniuk, the author of the book the movie is based on would disagree with you. For one, he has said he doesn't believe in the term toxic masculinity. He has said that Fight Club is "about empowering the individual and allowing the individual to make what they see as the best choice" and "about the terror that you were going to live or die without understanding anything important about yourself".
He has also remarked about how few cultural narratives there are for young men today, "I feel a little frustrated that our culture hasn’t given these men a wider selection of narratives to choose from. Really, the only narratives they go to are The Matrix and Fight Club".
As for the snowflake term being co-opted, he says, "once that material passes on to an audience, the audience adopts it. It will become the child of the audience and will serve whatever purpose the audience has for it. It would be insane to think that the author could control every iteration or every interpretation of their work."
For me, Fight Club was a very nihilistic (Chuck Palahniuk admits to being somewhat of a nihilist) and also very hopeful book (and movie), which is a tough combination to pull off.