Toast and soak chiles: Add guajillo chiles and chiles de arbol to a cold, medium nonstick pan. Warm over medium heat. Toast, flipping occasionally, until fragrant, about 4-6 minutes. Remove from pan. Remove and discard stem and seeds. Add chiles to a bowl, pour over boiling water to just cover peppers. Cover bowl with foil and allow peppers to soften for 45 minutes. Transfer chiles and chipotle in adobo to a food processor or blender with ¼ cup of the chili soaking liquid. Blend until smooth. Pass through a fine mesh sieve, discarding any solids. Set chili puree aside. Reserve chili soaking liquid.
Brown beef: While peppers soften, brown the beef. Heat a Dutch oven or medium pot over medium-high heat. Pat beef dry and season with salt and pepper, tossing to evenly coat. Add 1 tablespoon of oil to the pot. Add beef to the pot in a single layer, cooking in batches as needed. Cook 6-8 minutes total, turning occasionally, or until browned on all sides. Use an additional tablespoon of oil, as needed, while batch cooking beef. Set beef aside.
Make chili base: Reduce heat to medium to medium-low. Add the remaining tablespoon of oil to the pot. Add in onions. Sauté for 7-10 minutes or until well-softened but not burnt. Season with salt. Stir in garlic and cook 10 seconds. Stir in cumin, oregano, cocoa and cinnamon, and cook 10-15 seconds. Stir in chili puree. Add beer, increase heat and reduce volume by half. Add beef back to pot. Add 1 ½ cups stock or enough to cover the beef by 1 inch. Bring chili to a boil, reduce to a simmer and partially cover.
Cook chili: Simmer chili, stirring occasionally, for approximately 2 1/2 to 3 hours or until meat is very tender but not falling apart, and broth is thickened. Add more liquid to chili as it cooks to maintain desired consistency. I added water during cooking. If your stew would benefit from more flavor and is not at risk of becoming too salty, feel free to add more broth. If you prefer a spicier chili, add reserved chili soaking liquid. But be careful! The flavors will concentrate as it thickens. During the last couple minutes of cooking, add sugar and vinegar, to taste. Start with ¼ teaspoon of each, and add up to 1 teaspoon, if desired.
Serve: Scoop chili into bowls and top with sour cream, sliced scallions and grated cheddar. Serve with lime wedges for squeezing and chips for dipping! Enjoy.