Heat the dry pot over medium-high for 2 minutes. Add corn in a single layer and cook for 6–8 minutes, stirring only every 90 seconds, until scattered kernels have brown edges. Transfer to a plate.
Add 1 tablespoon oil to the pot. Crumble in the beef, season with 1 teaspoon salt and the black pepper, and cook for 8–10 minutes until browned and the center reaches 160°F (71°C). Transfer to a plate and spoon off excess fat, leaving about 1 tablespoon.
Add remaining oil if needed. Cook onion, bell pepper, jalapeño, and remaining ½ teaspoon salt over medium heat for 7–9 minutes until softened. Add garlic for 30 seconds, then stir in tomato paste and all spices for 90 seconds, moving constantly until fragrant and toasted.
Pour in 1 cup broth and scrape the bottom of the pot. Add the remaining broth (except the reserved ½ cup), both cans of tomatoes, black beans, pinto beans, and browned beef. Bring to a gentle simmer and cook uncovered for 18–20 minutes, stirring twice.
Whisk masa harina into the reserved ½ cup broth until smooth, then pour into the simmering soup while stirring. Cook for 4 minutes, then stir in the charred corn.
Turn off the heat. Stir in lime juice and cilantro, rest for 5 minutes, and taste. Adjust salt, lime, or broth as needed. Serve with toppings at the table.