In a medium mixing bowl, whisk together the eggs, milk, a generous pinch of salt, and freshly cracked black pepper until the mixture is well combined and slightly frothy.
Heat a non-stick skillet over medium heat and add the olive oil or butter, allowing it to melt and coat the surface evenly.
Once the oil is shimmering or the butter is melted, add the diced bell peppers to the skillet. Sauté them for 2-3 minutes, stirring occasionally, until they become tender and vibrant.
Reduce the heat slightly, then pour the prepared egg mixture into the skillet over the sautéed peppers. Gently stir with a spatula to scramble the eggs for approximately 3-4 minutes, or until the eggs are set and no longer runny.
Remove the skillet from the heat, and fold in the chopped spinach and half of the shredded cheese. Stir until the cheese is melted and evenly distributed throughout the egg mixture.
Place the large tortilla flat on a clean surface or a plate. In the center of the tortilla, spoon the egg mixture, then layer the sliced avocado on top, followed by the remaining shredded cheese.
Carefully fold the sides of the tortilla towards the center over the filling. Begin rolling the tortilla from the bottom up, ensuring the filling is tightly packed inside to form a secure wrap.
If desired, return the wrap to the skillet and toast it over medium heat for 1-2 minutes on each side, or until the exterior is golden brown and crispy.
Once toasted, remove from the skillet and slice in half diagonally. Drizzle with hot sauce, if desired, before serving.