Godhunter by Isobel Lynn (A Tyranny of Angels #1)

Bryony Moss didn’t plan to become a god, but accidents happen, and giving up immortality once you have it is easier said than done. Convinced her life is in danger, she infiltrates the crew of the infamous Black Armada with plans to dispatch their godhunter before she is discovered. But all her plans begin to unravel as soon as she learns the truth.

Far from the ruthless pirates she imagined, the Black Armada are akin to ruthless librarians, distributing banned books to fight the tyrannical rule of the angels. Once she’s in, Bryony can’t imagine killing any of them. She might even be tempted to join them for real. To top it off, she seems to be falling for the flagship’s navigator, a kind but isolated giant named Michael.