Red Rising isn’t hard sci-fi, but it is more notably sci-fi as a series after the first novel and the weird little obvious Hunger Games sequence ends.

The combat-oriented Golds are also an obvious ripoff of 40k Space Marines and the author absolutely betrays the overall message in the third book but that’s not related to the question, I just hate that he did it.

There can be peasants and feudal social classes in sci-fi. Sci-fi explores how society will react to future events and technology, but you could absolutely have a, for example, post apocalypse sci-fi novel about knights fighting over fiefdoms with swords in the ruins of Earth.

One of the reasons Star Wars gets criticised for not being sci-fi is that the science just doesn’t matter to the story.

You could have told the exact same story with samurai/warrior monks, horses, and wooden sailing ships, so the science is an aesthetic, not a plot element.

Like, they have a literal slave race of androids, fusion, FTL, everything, and it just doesn’t fucking matter. There isn’t a robot uprising. Everyone’s poor for no discernable reason, despite AI being a thing and the society effectively having unlimited energy, etc etc etc.

Red Rising might have had their weird little Youth Death Tournament but there was a point to the society doing that, to create a militarised group of the next generation of the ruling class.

Why is there poverty in Red Rising? Because they’re eugenics powered space fascists and it’s a control mechanism.

Why is there poverty in Star Wars? Because Lucas apparently never considered it should be anything else.