Toast the dried guajillo and ancho peppers in a dry skillet over medium heat for about 2 minutes until fragrant, watching closely to prevent burning.

In a blender, combine toasted peppers, garlic, onion, cumin, oregano, and 1 cup of beef broth; blend until smooth to make the sauce.

Place beef chunks in a large pot and pour the blended sauce over them; add the remaining 3 cups beef broth and season with salt and pepper.

Bring to a boil over medium-high heat, then reduce heat to low, cover, and simmer for 120 minutes, stirring occasionally.

Remove the beef from the liquid and shred using two forks; reserve the cooking liquid for serving.

Lay a flour tortilla flat, add a portion of shredded beef and a generous sprinkle of cheese, then roll tightly, sealing the edges.

Heat about 1 inch of vegetable oil in a skillet to 350°F (175°C); carefully fry each bomb for 3-4 minutes per side until golden brown.

Transfer fried bombs to paper towels to drain excess oil and serve hot with the reserved dipping broth.