In a small bowl, mix together the soy sauce, dark soy sauce, oyster sauce, sesame oil, brown sugar, and water. Set aside.
Thinly slice the steak against the grain and place in a bowl. Add the baking soda, cornstarch, dark soy sauce, brown sugar, and avocado oil. Toss to coat and marinate at least 20 minutes.
Heat 1-2 tbsp oil in a large wok over high heat. Add the steak in a single layer and sear 1-2 minutes per side until browned and just cooked. Transfer to a plate.
In the same wok add a little more oil if needed. Stir-fry the ginger and onion 1-2 minutes until softened, then add the garlic and cook 30 seconds until fragrant.
Add the fresh rice noodles and green onions. Gently toss about 1 minute to loosen the noodles, then pour in the sauce and toss until evenly coated.
Add the bean sprouts and cooked steak. Toss 1-2 minutes until the sprouts soften slightly and the beef is heated through. Serve immediately.