Whisk together in a bowl: pickle juice, ranch dressing mix, and sugar (if using) then pour the mixture into a sealable bag, add the chicken cutlets and marinate for 4-6 hours.
Stir the two types of breadcrumbs together in a shallow bowl.
In a separate bowl, whisk together the egg, egg whites, flour, and garlic powder. Add salt and pepper, if desired.
Dip each chicken cutlet in the egg mixture, allowing the excess to drip off and then dip into the breadcrumb mixture. Make sure both sides are well coated.
Spray the bottom of the air fryer or the air fryer rack with cooking oil spray.
Place the cutlets onto the greased air fryer rack, making sure not to overlap (work in batches if needed), and spray the top generously with avocado oil spray to lightly coat all of the breading.
Air fry at 400 degrees F for 8-10 minutes. Flip each cutlet over after 5 minutes, spray with more cooking spray and continue cooking until the crust is crisp and golden and the chicken is cooked through (the internal temperature is at least 160 degrees). An average cutlet will be done around the 8-minute mark, but this can vary depending on the size of your cutlets and your air fryer. Check for doneness at the 8-minute mark with a meat thermometer so they don't overcook.
Chicken should register 160 degrees F with a meat thermometer when done.