In a large pot, combine the beef shank, water, diced onion, chopped celery, minced garlic, bay leaves, black peppercorns, and salt. Bring to a rolling boil, then reduce to low and simmer for about 2 hours.

Once the beef is tender, remove it using tongs and shred it into bite-sized pieces. Strain the broth through a fine-mesh sieve into a separate bowl.

Return the strained broth to the pot and bring to a simmer. Add diced potatoes and sliced carrots, cook for about 20 minutes until fork-tender.

Add diced zucchini, chopped jalapeños, corn, diced tomatoes, shredded cabbage, and tomato sauce. Simmer for another 10 minutes.

Return the shredded beef to the pot with fresh lime juice. Stir gently and adjust seasonings with salt and black pepper.

Ladle the soup into bowls and garnish with red pepper flakes, fresh cilantro, and lime wedges on the side. Serve with hot sauce if desired.