Mash the cream cheese, mayonnaise, mozzarella and 1/4 cup of the Romano cheese together in a medium bowl with a rubber spatula. Stir in the spinach, scallions, and garlic. Season to taste with the hot sauce. Spread in an 8-inch square baking dish and sprinkle with the remaining Romano cheese. (The dip can be covered and refrigerated for up to 1 day.)