Place 1/3 cup hot sauce and 2 tablespoons olive oil in a large bowl and whisk to combine.
Remove the leaves from 1 medium head cauliflower, then cut in half and remove the tough core. Cut the florets into 1 1/2- to 2-inch pieces (about 5 cups). Transfer to the bowl and toss until evenly coated.
Place 1/4 cup all-purpose flour, 1/4 cup cornstarch, 1 teaspoon garlic powder, and 1/2 teaspoon kosher salt together in a second large bowl and whisk to combine. Use a slotted spoon or your hands to transfer the cauliflower to the bowl, leaving any excess sauce in the bowl. Toss with your hands or the spoon to evenly coat the cauliflower in the flour mixture.
Heat a 5 1/2-quart or larger air fryer to 400°F. Arrange the cauliflower florets in an even layer in the basket or tray (a little overlap is okay). Air fry, tossing every 5 minutes, until the cauliflower is hot, crispy, and lightly browned, 15 to 20 minutes total.