Heat a dry skillet over medium heat and toast the guajillo, ancho, and chiles de árbol 30–45 seconds per side until fragrant and pliable, flipping when their color deepens. Move toasted chiles to a bowl and cover with hot water to soak 15 minutes until softened.

Drain the soaked chiles and add them to a blender with the quartered onion, garlic, quartered Roma tomatoes, apple cider vinegar, ground cumin, dried oregano, ground cinnamon, and 1 cup beef broth. Blend until completely smooth, scraping down as needed so the sauce looks uniform.

Heat a large skillet over high heat, then sear the beef chuck chunks 2–3 minutes per side until browned on all sides. Transfer to the slow cooker as soon as all sides are browned.

Place the seared beef in the slow cooker and pour the blended chile sauce over the top. Add the remaining 3 cups beef broth and the bay leaves, then season with salt until the broth tastes balanced.

Cover and cook on LOW for 8 hours, or on HIGH for 4–5 hours, until the beef is completely fork-tender and shreds easily. Keep the lid on to maintain steady simmering in the crockpot and check for tenderness near the end.

Remove the beef, shred with two forks, and discard bay leaves from the pot. Skim excess fat from the broth (consommé) if desired so the dipping liquid looks smoother.

Dip corn tortillas in the reserved consommé, then place them on a hot griddle and fry for 1 minute until softened and lightly browned. Flip, top with shredded Oaxaca or mozzarella cheese and the shredded beef, fold, and cook 1–2 minutes per side until crispy and the cheese is melted.

Serve the tacos with diced onion, chopped fresh cilantro, lime wedges, and a small bowl of warm consommé for dipping. Plate with extra consommé so each bite stays juicy and flavorful.