Of Kings and Fairies. The Cursed Princes, #5

Naomi Novik's Spinning Silver meets V. E. Schwab's Shades of Magic (but short)When the world is at war, there is no time for love. Or so Hugo, crown prince and traitor to his kingdom, believes when he is dragged home to account for his crimes. Crimes Hugo won't repent, because his father is a tyrant, and everything Hugo has done has been in an effort to save his beloved realm from war and destruction. As punishment, the King demands Hugo take the Gauntlet, a series of impossible tasks that, should he win, means Hugo can claim the crown and force the King to step down.
The King is unconcerned; no one has ever succeeded the Gauntlet. To try is suicide. To think you can win is madness. But Hugo has done impossible things before, and he seizes this final chance to save the realm. Only one thing stands in his way: Sylvaine Gage, renowned battle-witch and the King's trusted right hand. Gage accompanies Hugo on his quest, discouraging - and distracting - him at every turn. Hugo needs every ounce of his strength and cunning to succeed.
But as he tries and fails to attempt the Gauntlet alone, he must accept that sometimes trusting people and accepting help is necessary, and love might be what he's saving the realm for. Of Kings and Fairies is an enemies-to-lovers gaslamp fantasy romance. It is the fifth book in the Cursed Princes, a series of short yet thoughtful reads with fractured fairy tales, subverted gender roles and angsty happy endings.
Each title is a standalone romance but the books are best read in order to understand the series arc.