Preheat oven to 400°F (204°C). Line a baking sheet with foil and set a wire rack on top.
Gently mix ground beef with 2 tbsp barbecue sauce, salt, and pepper. Don’t overmix.
Divide into four portions and form into 3.5-inch wide, 0.5-inch thick patties.
Lay two bacon slices in an X. Place patty in center, top with pineapple, fold bacon ends over, and secure. Repeat.
Place burgers on rack and bake for 15 minutes.
Brush tops and sides with remaining 2 tbsp barbecue sauce.
Bake 10–15 more minutes until bacon is crisp and internal temp hits 160°F (71°C).
Broil or skillet-toast buns for 2–3 minutes.
Let burgers rest 5 minutes. Serve on buns with optional toppings.