Heat the olive oil in a large pot or Dutch oven over medium heat.
Add the ground beef (or turkey) and cook until browned, breaking it apart with a wooden spoon, about 5-7 minutes.
Drain any excess fat if necessary. Then, add the diced onion, garlic, and red bell pepper. Sauté for about 3-4 minutes until the vegetables are softened.
Stir in the diced tomatoes (with their juices), kidney beans, black beans, chili powder, cumin, smoked paprika, salt, and pepper.
Pour in the beef broth (or water) and bring the mixture to a boil.
Lower the heat, cover, and let it simmer for about 20 minutes, stirring occasionally.
Taste the chili and adjust seasoning if needed.
Serve hot, garnished with optional toppings like shredded cheese, sour cream, or chopped green onions.