Sometimes they make these movies by slapping the name of one IP on the script for another simply to retain the IP and cut losses on scripts bought.
That's what happened with
Starship Troopers. They took an unrelated script and slapped the name on it.
It's really frustrating because the movie is supposedly a satire/parody of the book but utterly fails in every way.
Namely, Johnny is
Filipino. Sure, he grew up in Brazil but ethnically his family is Filipino. He speaks Tagalog!
The book is also very progressive for the time in terms of representing racial diversity, women, and persons with disabilities in the military. If Heinlein had written it now, then I suspect he'd include brief references to marines being LGBT+ or autistic.
We don't get a lot of insight into how the Terran Federation is actually run. It's extremely vague and comes across as extremely cynical about human nature in spots (e.g. a teacher dismissing the Declaration of Independence as idealistic nonsense, when ironically nowadays only far leftists think that), but it's definitely not
obviously fascist as detractors claim (or dystopian, or utopian, either). It's basically Heinlein saying "I think human nature sucks, I'm angry about that, I'm not sure my fictional government can fix the problems."
I don't know how you could make a genuine satire of the book given that it doesn't provide much material to work with. Maybe depict the Federation as some kind of neutropia/uchronia where it's both militaristic and socialist? I bet that would make heads explode on both sides of the political isle. A society that is both socialist and respects the armed forces couldn't possibly exist, could it?