Heat olive oil in a large heavy pot over medium-high heat.
Add chopped onion and diced bell pepper if using; cook 2–3 minutes until softened.
Add minced garlic and cook about 30 seconds until fragrant.
Add ground meat, break it up with a spoon, and cook 6–8 minutes until browned with no pink.
Season the meat with salt and black pepper.
Stir in chili powder, cumin, and paprika if used; cook 1 minute to release aromas.
Pour in crushed or diced tomatoes with juice and broth or water; stir and bring to a simmer.
Add dry macaroni directly to the simmering sauce; cover pot, reduce heat to medium-low.
Simmer about 15 minutes, stirring occasionally, until pasta is tender but firm; add extra broth if needed.
Turn off heat and stir in shredded cheese until melted and creamy.
Taste and adjust seasoning with salt and pepper if necessary.
Serve hot, optionally garnished with fresh herbs, sour cream, sliced jalapeños, or chili flakes.