The Hyperion saga is very enjoyable. If you didn't read them already The Martian and Project Hail Mary by andy Weir are outstanding.

I read Solaris recently and was genuinely blown away. Anything from Ursala le Guin is also an excellent choice although I would suggest "the Dispossessed".

I really enjoyed the novel Children of Time by Adrian Tchaikovsky. As someone who also thoroughly enjoyed the Expanse this definitely gave me some similar vibes even though the stories aren't similar at all.

Asimov is really good. If you are hesitate you can read I, Robot. Which is a collection of short stories to give you an idea of his writing style.

His books are pretty quick reads and high quality.

Iain M Banks's Culture novels. User name is relevant.

A couple of standard favorites of mine:

The Fuzzy books by H. Beam Piper. First of three is even public domain:

https://www.gutenberg.org/ebooks/18137

These others may be harder to find... Steve Perry is known for his Star Wars and Aliens books, but he also has his own shared universe which is a good read:

The Matador Novels:
The Man Who Never Missed (1985)
Matadora (1986)
The Machiavelli Interface (1986)
The Omega Cage with J. Michael Reaves (1988)
The 97th Step (1989)
The Albino Knife (1991)
Black Steel (1992)
Brother Death (1992)
The Musashi Flex (2006)

Stellar Ranger series:
Stellar Ranger (1994)
Lone Star (1994)

Venture Silk series:
Spindoc (1994)
The Forever Drug (1995)

Standalones:
Trinity Vector (1996)
The Digital Effect (1997)

Infinity Gate by M. R. Carey while definitely not his best work (see The Book of Koli trilogy which is outstanding but more dystopian), is a fun multiversal sci-fi romp.

~~Not sure but maybe~~ probably the raw shark texts.

Dune. Also Diaspora by Greg Egan.

Both are on my top 3. Look em up, hard sci-fi if that's your thing.

If you haven't read the Bobiverse series yet, you're in for a treat. The first book is called We are Legion (We are Bob). The books are easy to read, and somewhat light-hearted, while tackling serious philosophical questions. The first 3 books are right at the top of my all-time favorite sci-fi.

I really enjoyed all the Polity novels by Neil Asher. They are more fantasy leaning than the Expanse and Pandora's Star but fit your bill for fast moving and fun to read.

I would usually recommend some Alastair Reynolds to anybody into science fiction. I always suggest starting with House of Suns because it's a stand-alone novel that is really good and will give you a pretty good idea of what to expect from his writing. But his Revelation Space series is where the bulk of his writing is. However, I wouldn't call his work fast paced. So you might not get into it.

I have recently been reading the Murderbot Diaries. They are extremely easy and enjoyable reads. Could definitely give those a try.

If you enjoyed Recursion, you would probably like another book by Blake Crouch, Dark Matter.

I'm enjoying To Sleep in a Sea of Stars by Paolini. Though it is a bit long, it has lots of character development and I thought had a similar vibe to the Expanse. Also available as an audiobook which is excellent.

On the lighter side there is The Long Way to a Small, Angry Planet by Chambers (1st of a series) which I think are all excellent Adult/YA Space Opera and more in line with the Weir books.

I've been on a real Alistair Reynolds kick lately and just finished House of Suns, which I think is his best. But a good entry point for him is definitely Revelation Space. Good space opera with some gothic elements that I wasn't expecting.