Add 1 cup of broth to deglaze the pot; then pour in the remaining broth along with mushrooms (if using), soy sauce, rice vinegar, and sesame oil. Simmer for 30 minutes.
While simmering, mix vegan sausage filling ingredients in a bowl until combined.
Drop teaspoon-sized filling into simmering broth and cook for about 15 minutes.
Stir in bok choy; cook until just tender.
Gradually add wonton wrappers while stirring gently to prevent sticking. Simmer for an additional few minutes.
Serve hot, garnished with sliced green onions and a drizzle of chili oil if desired.