Prep the peppers: Slice the tops off the bell peppers. Remove seeds and membranes.
If they wobble, trim a thin slice off the bottoms so they stand upright without cutting into the cavity.
Preheat the air fryer: Set to 360°F (182°C). Lightly spray the basket with cooking spray to prevent sticking.
Cook the aromatics: Warm the olive oil in a skillet over medium heat. Add onion and cook 3 to 4 minutes until softened.
Stir in garlic for 30 seconds, just until fragrant.
Brown the meat: Add the ground beef or turkey to the skillet. Cook, breaking it up, until no longer pink, 5 to 7 minutes. Drain excess fat if needed.
Season and mix: Stir in the cooked rice, diced tomatoes, tomato sauce, Italian seasoning, smoked paprika, salt, and pepper.
Taste and adjust seasoning. Let the mixture simmer 2 to 3 minutes to thicken slightly.
Stuff the peppers: Spoon the filling into the peppers, packing it in gently and mounding slightly on top. Sprinkle about half the cheese over the filling.
Air fry: Arrange the peppers upright in the air fryer basket.
Cook at 360°F for 10 to 12 minutes until the peppers are tender but still hold their shape.
Add more cheese: Open the basket, top with the remaining cheese, and air fry 2 to 4 more minutes until melted and lightly browned.
Finish and serve: Let the peppers rest 3 minutes. Garnish with chopped parsley or basil. Serve with extra tomato sauce if you like.