In a small saucepan, combine the tomato sauce, BBQ sauce, vinegar, salt, garlic powder, and onion powder. Simmer over low heat, stirring constantly, 3 to 4 minutes. Remove from heat and cool slightly.
In a large bowl, combine the beef, pork, breadcrumbs, egg, dried onion, salt, garlic powder, and pepper.
Add ¾ cup of the glaze and mix by hand just until evenly combined. Do not overmix.
Grease a loaf pan. Press the mixture in evenly, flatten the top, and spread the remaining glaze over the surface.
Air fryer: preheat to 350°F, place the pan in the basket, and cook 35 to 45 minutes. Oven: preheat to 350°F and bake on a rimmed sheet 55 to 65 minutes. Tent with foil if the top browns early.
Cook until an instant-read thermometer in the center registers 160°F.
Drain off rendered fat, rest 10 minutes, then slice and serve.