Combine soy sauce, white vinegar, water, sugar, corn syrup, cider vinegar, pepper, yeast extract spread, sesame oil, garlic powder, onion powder, and ginger in a bowl. Mix well and pour sauce into a pot.
Pour 1/4 cup sauce into a small bowl. Add cornstarch; mix and add back to the main sauce.
Pour another 1/4 cup sauce into the bowl; add xanthan gum. Mix and pour through a strainer back in the main sauce.
Heat the pot of sauce over medium heat. Cook, whisking briskly, until gooey and thickened, 6 to 10 minutes. Strain sauce into a container; cover with plastic wrap and let cool.