Heat a large skillet or saucepan over medium-high heat. Add the ground beef and sausage and cook, breaking up the meat, until browned and no longer pink, about 5–7 minutes.
Add the diced onion to the skillet with the meat and cook until softened, about 3–4 minutes; then stir in the minced garlic and cook 30 seconds more.
Drain any excess fat from the skillet, return it to the heat, and stir in Italian seasoning, kosher salt, and black pepper.
Add the crushed tomatoes and diced tomatoes to the meat mixture and stir until combined.
Stir in the Worcestershire sauce (or coconut aminos) and the sugar (or brown sugar or maple syrup) if using; taste and adjust seasonings. If you prefer a thinner sauce, add up to 1 cup of water.
Bring the sauce to a gentle boil, then reduce heat to low and simmer, uncovered, for 15 minutes to blend flavors.
Remove from heat and serve over cooked spaghetti or your preferred pasta.