Heat oil in a large pot over medium heat. Add onions and cook, stirring occasionally, until they are slightly softened and translucent, approximately 5 minutes.

Stir in garlic and cook for an additional 1 minute until fragrant.

Introduce tomato paste, ensuring the vegetables are evenly coated. Add ground beef, breaking it up with a spoon, and cook until it is no longer pink, about 7 minutes. Drain any excess fat.

Add chili powder, oregano, cumin, paprika, and cayenne (if desired). Generously season with salt and black pepper.

Pour in tomatoes and beans, bringing the mixture to a boil. Reduce heat to medium and simmer, stirring occasionally, until the flavors have melded, and the liquid has slightly reduced, approximately 20 minutes. Adjust seasoning with salt and black pepper if necessary.

Ladle the chili into bowls.

Garnish with shredded cheese, a dollop of sour cream, and chopped scallions.