All 110VAC appliances can only give you 1,800 watts of heating maximum. So the max heating you can get is a function of insulation and volume of the space to be heated.

Air "frying" needs high heat, a big counter top oven can't give you very good insulation and it has a large volume of space to be heated. Also an air fryer needs high speed air movement, a convection fan in a counter top oven is not capable of giving air speed powerful enough to "fry" food.

dcarch