Chili Dog Mac and Cheese

Name: Chili Dog Mac and Cheese
Ingredients: 2 tablespoons vegetable oil; 1 large white onion, finely chopped; 1 pound lean ground beef; Kosher salt and freshly ground pepper; 1 tablespoon chili powder, plus more to taste; 1 teaspoon ground cumin; 1/2 teaspoon garlic powder; 1 15-ounce can tomato sauce; 2 tablespoons ketchup, plus more for serving; 1 pound small shells or elbow macaroni; 3 tablespoons unsalted butter; 3 tablespoons all-purpose flour; 3 cups whole milk; 1 pound cheddar cheese, shredded, plus more for serving; 8 ounces Velveeta or other processed cheese, cubed; 2 tablespoons yellow mustard, plus more for serving; Few dashes of hot sauce; 1 10-ounce package hot dogs, sliced into rounds; Relish, for topping