Heat a large pot or Dutch oven over medium heat. Brown the sausage or beef, breaking it up as it cooks. Drain excess grease if needed.
Add onion and cook 3–4 minutes until softened. Stir in garlic, Italian seasoning, red pepper flakes, salt, and pepper.
Pour in marinara sauce and broth. Whisk in the bone broth collagen until fully dissolved.
Bring to a gentle boil. Add uncooked ziti, reduce heat, and simmer uncovered for 10–12 minutes, stirring occasionally, until pasta is tender. Add water if needed.
Lower heat and stir in heavy cream and ricotta until smooth and creamy.
Taste and adjust seasoning. Serve hot topped with mozzarella, Parmesan, and fresh herbs.