In a large, deep pot or Dutch oven, heat the olive oil over medium-high heat. Add the ground beef. Break it up using a wooden spoon and cook until it is fully browned, about 6 to 8 minutes.

Drain off excess grease from the pot if desired, leaving a little for flavor.

Reduce the heat to medium. Add the diced onion and bell pepper to the pot. Sauté until the vegetables soften, about 4 to 5 minutes. Then, stir in the minced garlic for about 30 seconds until fragrant.

Stir in the taco seasoning, cumin, and smoked paprika. Cook for about 1 minute, stirring constantly to toast the spices.

Pour in the Rotel diced tomatoes (undrained). Add the 4 cups of beef broth. Stir well, scraping up any browned bits from the bottom of the pan. Bring to a simmer.

Add the elbow macaroni to the pot. Stir to ensure it's submerged. Reduce heat to prevent boiling over. Cook uncovered for 10 to 12 minutes, stirring every couple of minutes, until pasta is al dente and most liquid is absorbed.

Remove from heat. Stir in the milk. (Optional: Stir in 4 ounces softened cream cheese for extra creaminess.)

Sprinkle in the shredded cheddar cheese. Stir until completely melted and sauce is thick and glossy.

Let rest for 5 minutes. Garnish with fresh cilantro and sour cream if desired. Serve hot.