Preheat your air fryer to 400°F (200°C).
Pat the sirloin steak dry with a paper towel and cut it into uniform 1-inch cubes.
Prepare the vegetables by cutting the broccoli into small florets and slicing the red bell pepper into bite-sized pieces.
In a large mixing bowl, combine the steak cubes, broccoli florets, and bell pepper pieces.
Drizzle the avocado oil over the mixture and sprinkle with garlic powder, onion powder, smoked paprika, sea salt, and black pepper.
Toss everything together until the steak and vegetables are evenly coated with the oil and spices.
Place the mixture into the air fryer basket in a single layer, ensuring there is enough space for air to circulate.
Air fry for 8 to 10 minutes, shaking the basket halfway through the cooking time, until the steak is browned and the vegetables are tender and slightly charred.