Heat olive oil in a large heavy-bottomed pot over medium-high heat.
Add the ground beef and Italian sausage, breaking them up with a wooden spoon, and cook until browned, about 10 minutes, then drain excess fat.
Add the diced onions and bell pepper to the pot and cook until softened, about 6 minutes.
Stir in the garlic and cook for 1 minute until fragrant.
Add the chili powder, cumin, smoked paprika, cayenne pepper, salt, and black pepper, stirring constantly for 1 minute.
Mix in the tomato paste and cook for 2 minutes, stirring frequently.
Add all three types of beans, crushed tomatoes, and beef broth, stirring well to combine all ingredients.
Bring the chili to a boil, then reduce heat to low, cover partially, and simmer for 2 hours, stirring every 20 minutes.
Remove from heat and let stand for 10 minutes before serving to allow the chili to thicken.