Preheat the oven to 325°F. Lightly spray a rimmed baking sheet with cooking spray.
In a medium skillet over medium heat, add 2 tablespoons olive oil. Add the onion and ½ teaspoon of salt. Cook, stirring occasionally, until the onions are very tender and lightly browned around edges, about 7 to 10 minutes. Stir in the garlic and cook for 2 minutes more. Remove from heat and let cool while proceeding.
In a large bowl, stir together the panko and milk. Let the mixture stand for 5 minutes. (This allows the panko to absorb the milk for a juicy meatloaf.)
Stir the eggs, remaining 2 tablespoons of olive oil, 1 tablespoon Worcestershire, pepper, and 1 teaspoon of salt into the panko mixture. Add the cooled onion mixture and the turkey. Using your hands, gently mix together until all of the ingredients are just combined, being careful not to squeeze the turkey with your hands. Turn the mixture out onto the prepared baking sheet and shape it into a 9x4-inch loaf.
In a small bowl, whisk together ketchup and the remaining 1 tablespoon Worcestershire sauce. Reserve 1 cup, cover, and set aside.
Brush the meatloaf with a third of the remaining ketchup mixture and place in the oven.
Bake for 20 minutes. Brush again with another third of the ketchup mixture and return to the oven for 20 minutes. Repeat the brushing one more time, and continue baking until a meat thermometer inserted into the center of the loaf registers 165°, about 35 minutes more. Remove from the oven and allow the meatloaf to rest for 15 minutes. Serve warm with the reserved ketchup mixture.