Once Upon a Time in Hollywood was a real stinker of a film, IMO. I'd be highly surprised if young people used it as a benchmark of much. I didn't even remember "he" was in it until this comment.
Movie wad fantastic. The Bruce Lee scene is fucking hilarious also.
I thought it was hilarious myself, and however "correct" or not did establish his character as completely badass.
I certainly hope young people understand not to think of portrayals of real people in works of art+semi-fiction aren't a good representation to bench anything on.
Tarantino's style is so distinctive, and basically never grounded in reality.
Regardless of whether the film is to one's tastes or not, it would be a pretty grave error to encounter a character in a Tarantino film and mistake the performance as an accurate representation of any real world person.