The Ink Between Worlds. The Book Of Doors, #1

The map was wrong. So Saldara redrew it - and the world rearranged itself to match. Saldara Dossen is the finest cartographer in Yaros, and she has spent eleven years calling her secret "observational error." When she maps a thing, the land moves to obey her ink. An oak tree shifts down a valley overnight. She tells no one. She barely tells herself. Then the darkness folds, and she is pulled across a threshold into Voltana - a dying world of black towers and two bruised moons, unmade a little more with every passing night - by the one man who knows precisely what she is.
Zamir is Frayya: controlled, exacting, and nearly out of time. Three cartographers have already failed to save his world. He doesn't need a surveyor. He needs someone who can map what was - the lost bones of Voltana - and draw it back into being before the unmaking swallows everything. He needs her. And the deeper she descends into the truth beneath his city, the harder it becomes to keep her hands steady anywhere near him.
But a three-hundred-year-old letter waits in the archive, written in her own private notation by a woman who came before her - and loved before her. The door Saldara is racing to open was built for something. And it has been waiting a very long time to come through. To save a world, she'll have to do the one thing no map is meant to do: tell the truth so completely it becomes real. A slow-burn romantasy of competence, longing, and the terrifying intimacy of being truly known.