Pat cube steaks dry. Whisk flour, salt, pepper, garlic powder, onion powder, paprika, and cayenne in one shallow dish. Whisk eggs, buttermilk, and hot sauce in another.
Dredge each steak in flour, dip in buttermilk mixture, then return to flour and press coating on firmly. Rest on a wire rack 10 to 15 minutes.
Meanwhile, make the gravy: melt butter over medium heat, whisk in flour, and cook 1 to 2 minutes. Slowly whisk in milk. Simmer 4 to 6 minutes until thick. Season with salt, pepper, and garlic powder. Keep warm over low heat.
Preheat air fryer to 400°F for 3 to 5 minutes. Spray basket.
Spray both sides of steaks generously with oil. Place in a single layer. Air fry 6 minutes, flip, spray again, and cook 5 to 6 more minutes until golden and crisp (145°F internal). Keep warm in a 200°F oven if cooking in batches.
Fry eggs to order in butter. Cook hash browns.
Plate steak, ladle gravy over the top, add extra black pepper, and serve with eggs, hash browns, and toast.