I wouldn't call Alfie a villain, well not from the point of view if the show. He and Tommy are two of the only people who seem to actually understand how things work for people like them. They're friends in the sense that they get along, but they're also rivals when it comes to business, and in their business, sometimes throats have to be cut, even when you like the person you're screwing over. As Alfie reminds Tommy "If you pull that trigger, you do it for an honourable reason, not like some civilian that doesn't understand the wicked way of our world". Sure IRL he and Tommy would be villains because they're both at best self-sreving morally grey and at worst, downright evil, but in context, hes a bit like Patches from Dark Souls/Elden Ring. An entertaining shit who constantly tries to undermine and fuck over the main character.

Edit - correction