In a mixing bowl, whisk together soy sauce, gochujang, sesame oil, brown sugar, minced garlic, and ground black pepper. Add steak and marinate for at least 30 minutes.

Preheat grill over medium-high heat. Grill marinated steak for 3-4 minutes per side for medium-rare. Let rest for 5 minutes before slicing.

Boil water in a pot and cook instant ramen noodles for 2-3 minutes until al dente. Drain and rinse under cold water.

In a pot, heat chicken or beef broth until simmering. Stir in gochugaru, soy sauce, rice vinegar, sesame oil, and salt. Simmer for 2 minutes.

In a small bowl, mix mayonnaise, sriracha, sesame oil, and garlic powder until smooth. Adjust sriracha for spice level.

Serve ramen noodles in bowls, ladle hot broth over it, top with grilled beef slices, drizzle creamy sauce, and garnish with green onions and sesame seeds.