Pour tomato sauce into a large stockpot; bring to a simmer over medium heat. Reduce heat to low; keep sauce warm while preparing meatballs.
Set an oven rack about 6 inches from the heat source and preheat the oven's broiler. Line a baking sheet with aluminum foil; brush lightly with oil.
Combine bread crumbs, milk, egg, Italian herb seasoning, olive oil, garlic powder, and red pepper flakes in a small bowl until forms a thick slurry; set aside.
Combine beef and veal in a large bowl; season with salt, black pepper, and white pepper. Sprinkle with Parmigiano-Reggiano cheese. Add slurry mixture; mix until combined.
Scoop meat mixture using a small ice cream scooper into about 48 meatballs; place on the prepared baking sheet.
Cook under the preheated broiler until browned, 4 to 5 minutes; flip meatballs. Broil until no longer pink in centers and browned on both sides, 3 to 4 minutes more.
Transfer meatballs to the simmering tomato sauce. Increase heat to medium; cook for 5 to 10 minutes.
