Place vinegar and chiles in a small bowl; set chile vinegar aside.

Place fresh wide rice noodles in a large bowl of cold water and gently use your fingers to separate noodles to prevent them from clumping when cooking. If using dry noodles, prepare according to package directions.

Whisk together 2 tablespoons of the soy sauce, cornstarch, and baking soda in a medium bowl until combined and slightly foamy, about 5 seconds. Add sliced skirt steak and marinate for 10 minutes. Whisk together remaining 2 tablespoons soy sauce, oyster sauce, dark soy sauce, fish sauce, and sugar in a small bowl; set aside. Lightly beat eggs in a separate small bowl; set aside.

Heat oil in a large wok over medium-high. Add garlic and cook until sizzling, about 15 seconds.

Add sliced meat and stir-fry until lightly browned, about 1 minute. Reduce heat to low and add drained noodles, Chinese broccoli, and reserved soy sauce mixture, gently folding ingredients together until evenly coated, about 1 to 2 minutes. (Be gentle while stirring the noodles; you don’t want to break them.)

Push noodles to the side of wok, increase heat to medium and add eggs to empty side. Working quickly, cook and fold eggs into noodles. Stir together until sauce is thickened and eggs are cooked, about 1 minute.

Turn off heat and serve with a sprinkle of white ground pepper and season with reserved chile vinegar.