Heartbeat among Ashes (en Inglés) - sarah shah

Lena survived the world's end, abandoned and hardened, learning to trust no one-not even herself. Then she met Rowan, a boy who should have been dead, yet moves, thinks, and feels in ways no undead ever has. As danger closes in-from human raiders, skeletal Hollowed, and the shadows of the past-Lena and Rowan must navigate fear, longing, and impossible choices.

Together, they discover that love can restore what death has taken, humanity is more than memory, and survival is only meaningful when it's shared. In a world where the dead remember, Lena and Rowan must decide what it truly means to live.