Combine the blueberries, peaches, vanilla extract, lemon juice, maple syrup, arrowroot, and salt in a bowl and toss to combine. Pour mixture into the baking dish.
Combine all the topping ingredients in a separate bowl and stir until clumps form, then spread evenly over the fruit mixture.
Select the Preheat function on the Cosori Smart Air Fryer Toaster Oven, adjust temperature to 350°F, and press Start/Pause.
Place the baking dish on the wire rack, then insert rack at low position in the preheated oven.
Select the Bake function, adjust time to 1 hour, then press Start/Pause.
Remove crisp when golden on top and fruit is bubbly.
Serve with yogurt for breakfast or vanilla ice cream for dessert.