In a medium bowl, toss the steak cubes with olive oil until evenly coated.

In a small bowl, combine smoked paprika, garlic powder, onion powder, dried thyme, sea salt, and black pepper. Sprinkle this spice blend over the oiled steak cubes and toss well to ensure each piece is thoroughly seasoned.

Preheat your air fryer to 204 °C (200 °C) for at least 3 minutes.

Arrange the seasoned steak cubes in a single layer in the preheated air fryer basket. Avoid overcrowding the basket; cook in batches if necessary.

Air fry for 6-8 minutes, flipping halfway through, until the steak is browned on the outside and cooked to your desired doneness (internal temperature of 130-57 °C for medium-rare).

While the steak cooks, prepare the garlic-herb butter. In a small bowl, stir together the melted butter, chopped fresh parsley, minced garlic (if using), and red pepper flakes (if using).

Once the steak bites are cooked, transfer them to a clean bowl. Pour the garlic-herb butter mixture over the hot steak and toss gently to coat.