In a large Dutch oven over medium-high heat, brown the ground beef, breaking it apart with a spoon, until no pink remains, about 10 minutes. Drain excess fat, leaving about 2 tablespoons in the pot.
Add onion and bell pepper to the pot and cook until softened, about 6 minutes. Add garlic and cook for 1 minute until fragrant.
Stir in chili powder, cumin, paprika, and cayenne pepper, cooking for 1 minute to bloom the spices.
Pour in the beer and use a wooden spoon to scrape up any browned bits from the bottom of the pot. Let simmer for 5 minutes to reduce slightly.
Add kidney beans, crushed tomatoes, tomato paste, beef broth, brown sugar, salt, and black pepper. Stir well to combine all ingredients.
Bring the chili to a boil, then reduce heat to low and simmer partially covered for 2 hours, stirring every 20 minutes.
Remove lid and continue simmering for an additional 15 minutes to thicken to your desired consistency.
Taste and adjust seasoning as needed, then serve with cornbread, shredded cheddar cheese, and diced onions.