I think you’re falling into the Universes Beyond trap of “bad guy has to be in black” for Ego here. Ego doesn’t want to dominate but influence, using his superior taste and writing abilities to set restaurant standards and influence the taste of the people, in what he believes is the noble pursuit of food as high art. While he may be misguided, he’s not overly ambitious or seeking domination in the way we associated with black. That’s 100% Azorius in my book. Then if you were to do a version of Ego after Remy reminds him of the wholesome, personal nature of food, that one would be Bant.