Man, if you're craving that specific blend of danger, loyalty, and morally-gray passion, you can't start anywhere better than Cora Reilly's 'Bound by Honor'. It's basically the blueprint. The tension between the characters feels like a live wire, and the world-building around the Famiglia is so concrete you can almost smell the espresso and gun oil.
After that, the 'Camorra Chronicles' series by her gets even grittier. 'Twisted Loyalties' hits different—it's less about a polished, untouchable boss and more about a guy clawing his way up, which makes the romance feel earned and desperate in a really good way. For something that plays with the tropes in a newer way, Sophie Lark's 'Brutal Prince' series is a lot of fun. It's still all the power plays and violence, but the dialogue is sharper and the female leads often give as good as they get.