Brown the Sausage: Add the sliced beef smoked sausage to a stock pot (7-8 quarts) on medium-high heat. Cook for 5-6 minutes until the edges start to crisp and the fat renders. Transfer the cooked sausage pieces to a paper towel-lined plate to drain excess fat and set aside.
Cook the Beef Mixture: Add the lean ground beef, diced yellow onion, and minced garlic to the hot stock pot. Brown the ground beef for 5-6 minutes until no pink remains and the onions are tender. Drain any excess fat from the pot.
Combine All Ingredients: Return the cooked beef smoked sausage to the pot with the ground beef. Add the diced russet potatoes, beef broth, frozen sweet corn, frozen peas & carrots, pinto beans with liquids, stewed tomatoes, Rotel diced tomatoes & green chilies, chili powder, ground cumin, smoked paprika, salt, and black pepper. Stir thoroughly to combine all ingredients.
Simmer the Stew: Bring the Texas cowboy stew to a boil, then cover and reduce the heat to low. Allow to simmer for 1 hour or until the potatoes are fork-tender. Keep the lid slightly cracked to allow excess steam to escape during cooking.