Preheat oven to 225°. Mix 2 lb. ground pork and 1 lb. ground beef chuck (20% fat) with your hands in a large bowl; season generously with kosher salt and freshly ground black pepper, then mix again. Form into about 18 large meatballs.

Warm 2 Tbsp. extra-virgin olive oil in a large Dutch oven or other heavy pot over medium-high heat. Cook meatballs in 2 batches until browned all over, about 6 minutes per batch. Transfer to a rimmed baking sheet.

Reduce heat to medium. Add 2 oz. pancetta to pot and cook until lightly browned, about 5 minutes. Add onion, celery, carrot, and garlic; cook until softened, 6–8 minutes. Add tomato paste and cook until darkened, about 2 minutes.

Add ¾ cup dry white wine and cook until almost completely evaporated, about 5 minutes. Add whole peeled tomatoes, crushing with your hands, and increase heat to medium-high. Cook until liquid is jammy and reduced by about half, 8–10 minutes. Add chicken broth and whole milk, then return meatballs to pot. Bring to a simmer. Cover pot partially with a lid, transfer to oven, and cook until meatballs are tender, 3–4 hours.

Using a potato masher, break meatballs apart and incorporate into liquid. Taste and season with more salt and black pepper if needed.

Melt 7 Tbsp. unsalted butter in a large saucepan over medium heat. Whisk in ¼ cup plus 3 Tbsp. all-purpose flour and cook until mixture smells slightly nutty, about 4 minutes. Quickly whisk in 6 cups whole milk, then bring to a simmer, whisking constantly. Reduce heat and cook until béchamel thickens, about 4 minutes. Continue to cook until smooth and velvety, 8–10 minutes more. Remove from heat and whisk in Parmesan cheese, cayenne pepper, and nutmeg. Season with salt and pepper.

Preheat oven to 325°. Cook 1¼ lb. dried lasagna noodles in boiling salted water until just starting to soften, about 3 minutes. Transfer noodles to a bowl of cold water to cool. Drain and lie flat on a baking sheet.

Lightly coat a 13x9" baking dish with extra-virgin olive oil. Spread 1½ cups ragù in dish. Lay a single layer of noodles over ragù. Spoon 1¼ cups béchamel over noodles, then top with 1½ cups of meat sauce. Repeat process, creating 5 layers of pasta, ending with remaining 1 cup béchamel.

Cover with oiled aluminum foil and bake until bubbling, about 1 hour. Remove foil and bake until top is browned, 10–15 minutes longer. Let sit 10 minutes before serving.