Remove the ribeye steaks from the refrigerator 30-45 minutes before cooking to bring them to room temperature.
Pat the steaks completely dry with paper towels.
Drizzle both sides with olive oil and season generously with kosher salt, black pepper, and garlic powder. Don't forget the edges!
Preheat the air fryer to 400°F (200°C) for 4-5 minutes.
Place the steaks in the preheated air fryer basket in a single layer with space between them.
Cook for 6 minutes, then flip and cook for an additional 4-6 minutes for medium-rare, or until the internal temperature reaches 125°F (it will rise to 130-135°F as it rests).
Transfer the steaks to a cutting board, top with butter if using, and tent loosely with foil. Let rest for at least 5 minutes.
Serve immediately, slicing against the grain if desired.