Scrub the potatoes thoroughly and remove any soft spots or cuts.
Cut potatoes into evenly sized fries using a knife, mandolin, or fry cutter.
Soak the fries in a large bowl of cold water for 30 minutes, drain, replace with fresh cold water, and soak an additional 30 minutes to remove starch.
Preheat the air fryer to 375°F.
Drain and dry the fries thoroughly using paper towels.
In a large bowl, toss fries with olive oil and granulated garlic until evenly coated.
Arrange fries in a single layer in the air fryer basket and cook for 15 minutes.
Remove the fries, toss them, and return to the air fryer for an additional 5 to 10 minutes until golden and crispy.
While fries cook, prepare toppings by combining dried oregano, red onion, tomato, parsley, and crumbled feta in a bowl.
Transfer cooked fries to a serving plate, sprinkle with oregano, then top with onion, tomato, parsley, and feta.
Squeeze fresh lemon juice over the fries and season with salt and pepper to taste.
Serve immediately, optionally with tzatziki on the side or drizzled on top.