Place 6 chopped thick-cut bacon slices in a large Dutch oven or heavy-bottomed pot and cook over medium-low heat until browned and crisp, 8 to 10 minutes. Transfer the bacon with a slotted spoon to a paper towel-lined plate.

Increase the heat to medium-high. Season 1 (4- to 5-pound) chopped brisket all over with 1 teaspoon of the kosher salt. Working in 3 batches, add the brisket to the pot in a single layer and sear undisturbed until the bottom develops a dark brown crust, about 4 minutes. Stir and continue cooking until browned all over, about 4 minutes more. Using tongs or a slotted spoon, transfer to a large plate. Repeat searing the remaining brisket and transferring to the plate.

Reduce the heat to medium-low. Add 3 chopped dried ancho chiles and 1 finely diced large white onion to the pot. Scrape up any browned bits from the bottom of the pot and cook until the onion is softened and browned, about 5 minutes.

Stir in 2 finely chopped canned chipotle peppers in adobo sauce, 6 grated garlic cloves, 3 tablespoons chili powder, 2 tablespoons tomato paste, 1 tablespoon packed brown sugar, 2 teaspoons ground cumin, 2 teaspoons black pepper, 2 teaspoons smoked paprika, ¼ teaspoon ground cinnamon, and the remaining 1 teaspoon kosher salt. Cook, stirring constantly, until fragrant and lightly toasted, about 1 minute.

Stir in 12 ounces dark beer and 3 tablespoons masa harina, and repeat scraping up the browned bits from the bottom of the pot. Pour in 1 (32-ounce) carton low-sodium beef broth and 1 (28-ounce) can crushed tomatoes. Return the bacon and beef and any accumulated juices on the plate to the pot and stir to combine. Bring to a simmer. Reduce the heat to low.

Partially cover and simmer, stirring every 20 minutes or so, until the beef is fork-tender but not falling apart, 2 to 2 ½ hours. Taste and season with more kosher salt and black pepper as needed. Serve with desired toppings.