Merciless Queen by M.L. Philpitt

Vanessa Volkov began her life as a pawn. Being the Pakhan’s daughter, she was conditioned to obey, to be who her father demanded she be. After his death, Vanessa spends the next two years rising to the role of Pakhan, her rightful place as the only heir. But a throne claimed after a king’s fall is unstable, making the queen vulnerable to other players—even ones not yet revealed.
Zeno Mancini isn’t fooled by the woman nicknamed the Merciless Queen. A ruler she may be, but monarchies are historically known to crumble under threat. Despite his vendetta against the Bratva, Zeno keeps Vanessa alive because there’s numerous ways for the Volkovs to pay for past transgressions. I do is the equivalent of checkmate, and the Merciless Queen is now left to the mercy of her new king.