In a skillet over medium heat, warm the olive oil and sauté the ground beef along with the diced onion and minced garlic until the meat is thoroughly browned and the onions have softened; drain any excess fat. Transfer the cooked beef mixture to the slow cooker and incorporate the beef broth, diced potatoes, corn, Worcestershire sauce, ketchup, mustard, smoked paprika, salt, and pepper, stirring well to combine. Cover and allow to cook on low for 4–6 hours or on high for 2–3 hours until the potatoes become fork-tender and the ingredients are well integrated. About half an hour before serving, fold in the shredded cheddar and mozzarella cheeses until they are fully melted and blended. Just prior to serving, stir in the sour cream and adjust seasoning if needed. Ladle the soup into bowls and garnish with chopped green onions and crispy bacon bits, if using.