If not already done, cut wings into drumettes and flats and pat them dry with paper towels.
Place the wings in a large bowl and toss with 1–2 tablespoons avocado oil to coat evenly.
In a small bowl, whisk together salt, black pepper, baking powder, smoked paprika, garlic powder, onion powder, ground mustard, and cayenne (if using).
Sprinkle the seasoning mix over the wings and toss until all pieces are evenly coated.
Lightly spray the air fryer basket with nonstick spray and arrange the wings in a single layer without overcrowding; cook in batches if needed.
Air fry at 350°F for 8–9 minutes, then flip each wing and cook another 5–7 minutes until golden and crisp.
Remove the wings and brush each with low-sugar barbecue sauce.
Return the wings to the air fryer and cook an additional 3–5 minutes, until the internal temperature reaches 165°F and sauce is set.
Serve with extra barbecue sauce if desired and optional celery sticks and Greek yogurt for dipping.