Preheat the air fryer to 400°F (200°C).
In a medium bowl, toss the potato cubes with 1 tablespoon of olive oil, 0.5 teaspoon of salt, and 0.25 teaspoon of black pepper.
Place potatoes in the air fryer basket in a single layer and cook for 12 minutes, shaking the basket halfway through.
While potatoes cook, toss the steak cubes with the remaining 1 tablespoon of olive oil, 0.5 teaspoon of salt, 0.25 teaspoon of pepper, garlic powder, and onion powder.
Add the seasoned steak bites to the air fryer basket with the potatoes and cook for an additional 6 to 8 minutes until the steak reaches an internal temperature of 135°F (57°C) for medium-rare.
In a small bowl, combine the melted butter and minced garlic.
Transfer the cooked steak and potatoes to a large bowl, pour the garlic butter over them, and toss to coat evenly.
Garnish with fresh parsley and serve immediately.