In a small bowl, combine the vegetable stock, oyster sauce, low-sodium soy sauce, brown sugar, sesame oil, rice vinegar, corn starch, and pepper. Whisk until well mixed and set aside.
In a large wok or skillet, heat the vegetable oil over medium-high heat until shimmering.
Add the minced ginger and garlic to the hot oil. Stir-fry for about 30 seconds until fragrant, being careful not to let them burn.
Introduce the broccoli, red bell pepper, yellow bell pepper, carrots, sugar snap peas, mushrooms, and water chestnuts to the pan. Stir-fry for about 5-7 minutes, or until the vegetables are tender-crisp.
Give the sauce mixture a quick stir to incorporate the corn starch, then pour it over the sautéed vegetables. Stir well to coat everything evenly. Cook for an additional 2-3 minutes, allowing the sauce to thicken and the vegetables to absorb the flavors.
Remove the wok from heat. If desired, sprinkle sesame seeds and sliced scallions on top for garnish. Serve your Vegetable Stir-Fry hot over rice or noodles, and enjoy your flavorful, nutritious meal!