1. FOR THE SAUCE: Adjust oven rack to middle position and heat oven to 400. Heat oil in large saucepan over medium heat until shimmering. Add the garlic slices and cook until lightly browned, about 1 minute. Stir in tomatoes, tomato sauce, pepper flakes & salt. Bring t simmer and cook until flavors have melded, about 5 minutes. Remove from heat, cover to keep warm.
2. FOR THE MEATLOAF: Spray broiler safe 13x9 inch baking dish with vegetable spray. Place saltines in large ziplock bag, seal bag, and crush saltines to fine crumbs with a rolling pin. Whisk saltines, milk & eggs together in a large bowl. Let sit until saltines are softened, about 5 minutes. Whisk saltine mixture until smooth paste forms. Add beef, pork, sausage, Romano, chopped garlic, oregano, salt, pepper, and red pepper flakes and mix with your hands until thoroughly combined.
3. Transfer beef mixture to prepared dish. Using your wet hands, shape into 9 by 5-much rectangle; top should be flat and meatloaf should be 1-1/2 inches thick. Pour sauce over meatloaf. Cover with aluminum foil and place on rimmed baking sheet. Bake until meatloaf registers 160 degrees, 1 hour and 5 minutes to 1-1/4 hours.
4. Remove sheet from over, uncover dish and sprinkle evenly with mozzarella. Heat broiler. Broil meatloaf and cheese until cheese is melted, about 2 minutes
5. Using 2 spatulas, transfer meatloaf t cutting board. Spoon off any excess grease from tomato sauce. Slice meatloaf 1 inch thick. Transfers slices back into sauce in dish, sprinkle with basil, and serve.