Umbra (Sentient Stars #1) by Amber Toro
 
Umbra is the first book in the Sentient Stars trilogy, an intergalactic, space opera, adventure story, with a slow burn enemies to lovers romance, told from 3 POV’s with fully sentient starships, a militaristic society, alien worlds, and a signal in the darkness that threatens to destroy humanity.

Earth That Was has faded into myth. After millenia spent wandering, humans are no longer nomads. Twelve tribes stand allied under the United Tribal Axis; but there is a signal in the darkness that threatens to destroy everything.

All Skyla wanted after leaving the Navy was to be left alone. Just her ship, the stars, and a new adventure. But when a strange virus disables her ship, she is thrown into the middle of a conflict she doesn’t understand, forcing her to take on responsibilities she swore she never would again.

Hinata always followed the rules, honor above all else. He always won, until he didn’t. Sentenced to exile for his failures, he is determined to prove himself, until a mysterious woman arrives on his station and chaos threatens to break already fragile alliances.

Freyja was always angry, an outcast, playing the part of admiral and black ops operative. But she is tired of being a pawn in the Empress’ games and when she’s stranded on the wrong side of enemy lines after a vengeful battle, she’s forced to ally with her adversaries to clear her name.

A Rogue.
A Commander.
And an Admiral.

Brought together by circumstance, held together by duty.
Can they find a way to work together to save humanity?