These Violent Delights by Chloe Gong
The year is 1926, and a blood feud between two gangs runs the streets red, leaving the city helpless in the grip of chaos. At the heart of it all is eighteen-year-old Juliette Cai, a former flapper who has returned to assume her role as the proud heir of the Scarlet Gang--a network of criminals far above the law. Their only rivals in power are the White Flowers, who have fought the Scarlets for generations. And behind every move is their heir, Roma Montagov, Juliette's first love...and first betrayal.