Make the spiced apple drizzle (if using): Stir together the caramel sauce and 1 tablespoon apple brown sugar syrup until well combined and set aside.
Make the frappuccino: Add the ice, cold brew coffee, oat milk, 3 tablespoon apple brown sugar syrup, and xantham gum to a high-speed blender and blend until smooth.
Pour the frappuccino into a tall glass, then top with whipped cream and/or spiced apple drizzle if desired. Drink up!