I'm talking today as a reader, not a writer. I read a really cool SF book this week, Landfall by Jerry Aubin.
It's available here: on Amazon and for Prime members, it is currently free through the Prime Reading program. I've been trying various books on the program since it launched this month and this one is the real standout for me so far. https://www.amazon.com/Landfall-Ship-Book-Jerry-Aubin-ebook/dp/B018ZJHO24/
It's SF with spaceships, battles, aliens, a generational ship, and a cadre of military cadets in training. One reviewer calls it Enders Game meets Battlestar, and it is, while also being original. As a writer, I can see into the craft of this, and he's doing a whole lot of things right--as in how he gives you the complex worldbuilding while he's characterizing and creating tension, so it never feels like infodumping. The man knows his craft.
As a writer I can admire his talents, but it's as a reader I responded to it. It's pure geeky pleasure, intelligent SF, plausible future, science-based, with an incipient romance and a mystery all wrapped into the tale. Seriously, go get it, and if you have Prime, there is no reason not to! It's free, dude!
I sometimes mention my friends' books, but I feel compelled to mention that Jerry and I aren't friends (yet--life is long). I'm simply geeking out as a reader on this one.