Begin by generously seasoning the skirt steak with salt, freshly ground black pepper, and the minced garlic to infuse the meat with aromatic flavors. Next, chop one whole onion into four large wedges – these chunks will contribute depth to the broth as the beef cooks. Place the seasoned beef and the four onion wedges into your pressure cooker or Instant Pot. Pour in the beef stock, ensuring the meat is partially submerged to lock in moisture and tenderness during cooking. Secure the lid and cook under pressure for 20 minutes, allowing the beef to become tender and ready to shred. Once the cooking time is complete, carefully release the pressure before opening the lid. Remove the beef from the pot and set aside. Reserve 2 cups of the rich cooking stock in a separate container – this flavorful liquid will be used to enrich the sauce later. Using two forks, gently shred the warmed beef; it should pull apart easily if perfectly cooked. If the meat resists shredding, seal the lid again and cook for an additional 10 minutes to achieve the desired tenderness. Activate the sauté function on your Instant Pot and heat the olive oil. Once the oil is shimmering and the appliance beeps, add the sliced onion, red pepper, and thinly sliced tomatoes to the pot. Sauté these vegetables gently until they soften and release their natural sweetness, creating a delightful base for the sauce. Return the shredded beef to the pot, stirring it through the sautéed vegetables to blend the flavors. Pour in 1 1/2 cups of the reserved beef stock, followed by the Worcestershire sauce, tomato puree, tomato ketchup, and cumin powder. Stir everything together thoroughly, ensuring a harmonious mixture of all ingredients. Keep an eye on the sauce's consistency; if it appears too dry, gradually add more of the reserved stock to achieve a luscious, saucy texture. Taste and adjust the seasoning with additional salt and pepper as needed. Once the sauce is rich and the beef is well-coated, the dish is ready to serve. This Venezuelan shredded beef pairs wonderfully with warm arepas, white rice, or black beans, offering a comforting and satisfying meal that celebrates traditional Latin American flavors.