Not the person you asked, but I've seen The Expanse described as "hard" sci-fi. It's heavy on space technology, warfare, flight mechanics, things like that. A bit grim and dark at times.

Overall, The Expanse is the single greatest piece of sci-fi that I've ever personally seen. The show is so. Fucking. Good. It's hard to even explain it. The writing, the filming, the pacing, the way they shoot scenes... it's just a marvel to witness.

I'd say it is 'hard-ish' and grim, the setting at the start explores the social, labour, and warfare effects based on the premise of a hyper-efficient space ship drive. So it takes travel times, gravity, economics, etc, serious, there's some heart-rending stuff in there.

I think people tend to call it hard sci-fi mostly because it is pretty rare for tv sci-fi to really explore the mechanics of space travel to this type of degree but there's also a lot of stuff it omits. I think the show is really good at taking a slightly fanciful premise and exploring it in quite a thorough way. Maybe I'm cooled on it now that it's been a while since I watched it but I remember when it came out it was just amazing to have a ship dock with a spinning space station and realise it thought it through more than I had.

very politcal. Ive only read the book but it is probably the most 'realistic' depiction of humanity in space. I know some described the book as Game of Thrones in space but id argue its half that and half its own amazing thing.

no space magic. no warp drives, transporters. if you want to land on something you flip the craft around via RCS and hit the rockets while also strapped into chairs that keep you from stroking out from the g-forces kind of sci-fi.