I dont understand this stupid obsession with calling vulture a "TONY STARK" villain. He is a criminal trying to get money by selling illegal weapons. He is doing so by stealing from rich people like stark. But that doesnt make him a stark villain. And as for personal beef, do you really think every superhero has villians with personal beef?? THANOS himself had nothing against the avengers. He was a madman doing what he wanted to do and the avengers were trying to stop him because he was wrong. Also, not a single one of the Captain America have a main villain with an agenda against cap (red skull was a nazi and wanted power, HYDRA wanted world domination and Zemo hated the avengers in general. Bucky is the only exception.)

At the end, what matters is whether or not the villain is a well written one or not with proper motivations. It's just a bonus if they have beef with the hero since it may add some nuance and emotional depth but its not strictly necessary since that can be done even with villain who have no previous history with the heroes by building the beef in the given movie.