Preheat the air fryer to 400˚F (200˚C). Prepare three separate bowls for coating.
In the first bowl, combine 1/2 cup flour, 1/2 teaspoon salt, 1/2 teaspoon paprika, 1/2 teaspoon garlic powder, and 1/4 teaspoon cayenne pepper.
In the second bowl, whisk 2 eggs and 1 tablespoon water until smooth.
In the third bowl, combine 1 cup panko breadcrumbs with 1/2 teaspoon seasoned salt.
Dip each cauliflower piece first in the flour mixture, shaking off excess. Then dip in the egg mixture, allowing excess to drip off. Finally, coat thoroughly in the breadcrumb mixture, pressing gently to adhere.
Arrange coated cauliflower in a single layer in the air fryer basket, ensuring not to overcrowd. Cook for 15-20 minutes, flipping halfway through, until golden brown and crispy.