Bison Meatloaf Burgers with BBQ Sauce

Name: Bison Meatloaf Burgers with BBQ Sauce
Ingredients: Nonstick cooking spray, for the baking dishes; 1 cup ketchup; 1/4 cup dark brown sugar; 3 tablespoons garlic powder; 3 tablespoons onion powder; 2 tablespoons molasses; 3 teaspoons balsamic vinegar; 2 pounds ground bison; 10 cloves garlic, grated; 3 large eggs; 1 onion, grated on the large holes of a box grater; 2 cups ketchup; 1 cup Italian breadcrumbs; 2 tablespoons ground cumin; 2 tablespoons garlic powder; 2 tablespoons sumac; Kosher salt and freshly ground black pepper; 8 burger buns, toasted