The Tower and the Final City
Just beyond our reality: an ancient, dying world dominated by an endless crumbling City that stretches in every direction from the monolithic Tower at its heart. In that Tower, an Academy that teaches girls how to control their inherent magical talent, under the watchful eye of the Headmistress and the Tower itself, sapient, incomprehensible and ominous. Magic with the power to rewrite the laws of reality, cast the sun out of the sky, and unravel the very fabric of the universe.
Enter Riley, who is notable in three ways. One, Riley stumbled into this magical place accidentally. Two, Riley can perform strange and unexpected feats of magic that are beyond even skilled Adepts. And three:
Riley is a boy. And only girls can do magic.
(The protagonist of this novel is a transgender girl who is still very closeted. It includes multiple sapphic and polyam relationships, a diverse young adult cast, and an intuitive but complex magic system.)