Heat a Dutch oven over medium heat and add the oil. Add the onion, bell pepper, and celery with a sprinkle of salt. Cook, stirring frequently, until the onions are translucent and the veggies are starting to brown, 7-10 min. If things are sticking to the pan, feel free to add a splash of water.
Add the garlic, chili powder, paprika, oregano, garlic powder, onion powder, thyme, cayenne (if using), salt, pepper, and sausage with a splash of water to scrape up the brown bits. (You can also use a little bit of dry red wine here; it's called deglazing the pan). Stir until the spices evenly coat the ingredients and cook until the sausage is nearly done, 5-7 min.
Add the tomatoes (including their juices), broth, and pasta. Increase the heat until the mixture comes to a low boil. Stir well, cover, and reduce to a low simmer for 10 minutes. Stir occasionally and monitor the water level. If the liquid seems to be evaporating quickly, reduce the heat a little and add water as needed. If the pasta is almost ready but the rest looks too soupy, let it cook with the lid off for a minute or so.
When the pasta is ready, reduce the heat. Add the milk and cream cheese and stir until the cream cheese is fully melted and incorporated. Add the Parmesan cheese gradually, if using, and stir until melted. The sauce will thicken as it cools so don't be alarmed it initially looks like there is extra liquid.
Assemble. Divide the pasta among three meal prep containers and allow to cool completely before refrigerating Garnish with parsley (if desired).