Add olive oil to a skillet set over medium-low heat. Sauté onion and garlic for around 8 minutes until caramelized. Then set aside to cool.
While the onions cook, combine the breadcrumbs, Worcestershire sauce, milk, eggs, salt, and pepper in a large mixing bowl and stir until well combined. Let sit for around 5 minutes to hydrate the breadcrumbs.
After the onion and garlic have cooled, add to the breadcrumb mixture and the ground beef. Wet your hands and mix thoroughly, but avoid overworking the meat.
Form the mixture into a rough ball, then turn it out onto a grill basket or disposable grill topper. Pat down the ball to a rectangular shape around 2 ½ to 3 inches thick.
Add the meatloaf to your smoker with a drip pan set underneath if possible. Then add wood chunks to the smoker and cook for 2 hours.
While the meat cooks, combine the ketchup and barbecue sauce in a small bowl. Open your smoker and, using paper towels, blot any fat that has collected on the top of the meatloaf. Brush the sauce mixture on the top and sides of the meatloaf and cook for another 30 minutes to an hour, until the internal temperature reaches 160°F in the center of the meatloaf.
Let the meatloaf rest for 10 minutes before slicing and serving.