Bring a large pot of salted water to a boil over high heat. Add dry macaroni and cook until al dente, following package instructions, about 8-10 minutes. Once cooked, reserve pasta water, then drain the macaroni and set aside.

In a large skillet, melt butter over medium heat. Add minced garlic, chopped white onion, and red, green, and yellow bell peppers. Sauté for 4-5 minutes until vegetables soften and onions become translucent.

Crumble in lean ground beef into the skillet and cook for 5-7 minutes, breaking it apart as it browns. Drain any excess fat and season with salt, pepper, paprika, and chili flakes to taste.

Lower the heat to low and stir in light cream cheese, shredded mozzarella, and cheese slices. Stir until the cheeses melt and blend into a smooth sauce.

Add the drained macaroni to the skillet along with reserved pasta water. Stir everything together until the pasta is coated in the creamy cheese sauce. Adjust the consistency as needed.