In a small bowl, whisk together soy sauce, oyster sauce, sesame oil, garlic paste, ginger paste, brown sugar, white pepper, and cornstarch.
Heat olive oil in a large skillet over medium-high heat. Add onion, celery, and cabbage. Sauté until fragrant and tender, about 5-7 minutes.
Add noodles and the seasoning packet. Pour in the sauce and toss everything together until well combined and evenly coated.
Cook for an additional 3-5 minutes until noodles are heated through and slightly crispy in some spots.
Garnish with sliced scallions and serve immediately.