Remove steaks from the refrigerator 30 minutes before cooking to bring to room temperature.
Pat steaks thoroughly dry with paper towels to facilitate browning.
Preheat the air fryer to 400°F (200°C).
Coat the steaks with avocado oil and season all sides evenly with salt, pepper, and garlic powder.
Place steaks in the air fryer basket, ensuring they do not touch.
Cook for 12 minutes, flipping the steaks at the 6-minute mark.
Verify internal temperature reaches 130°F (54°C) for medium-rare using a digital meat thermometer.
Remove steaks from the air fryer and top with a pat of butter and rosemary.
Rest the meat for 5 to 10 minutes before slicing to retain moisture.