First, prepare the breakfast potatoes. In a large frying pan, heat vegetable oil over medium-high heat until shimmering. Add cubed potatoes and season with salt and pepper. Cook until crispy, turning over occasionally, about 20 minutes. Then remove from heat and set aside.
While the potatoes are cooking, prepare the cheesy scrambled eggs. Preheat a lightly greased frying pan over medium-low heat, then whisk together eggs and milk in a small bowl. Transfer eggs to the frying pan and cook until slightly firm on top, about 5 to 7 minutes, then scramble and cook until warmed through, about 2 to 3 more minutes. Lower heat and stir in shredded mexican-blend cheese until melted, then remove from heat and set aside.
Prepare the remaining burrito fillings. Mash avocado in a small bowl and stir in lime juice and sea salt, then set aside. Warm refried beans in the microwave for about 1 to 2 minutes, stirring occasionally, then set aside. Warm the flour tortilla in the microwave between two sheets of dampened paper towels for about 30 seconds.
Assemble the burrito. Lay down the tortilla on a large sheet of aluminum foil. Spread the refried beans over the tortilla, then top with scrambled eggs, potatoes, and a drizzle of roja hot sauce in a line down the center of the tortilla. Finally, top with chopped bacon, pico de gallo, and mashed avocado.
Carefully fold the burrito using two hands. Fold opposite sides into the center, then use your pinky fingers to pinch the sides of the burrito in as you roll it over itself in the other direction. Quickly wrap with aluminum foil to hold everything together.
Transfer to a cutting board and slice the burrito in half with a large, sharp chef's knife. Serve immediately!