When selecting a bbq sauce, remember that some bbq sauces are already sweet, so you might want to cut back on the brown sugar, but don't cut it out completely. Brown sugar is needed to help the jackfruit caramelize and brown. Ideally, look for a low-sugar or sugar-free bbq sauce.
As a side note, the longer you simmer the mixture, the deeper the flavour will be. Even though this dish is ready in 45 minutes, you can leave the "meat" to simmer for a longer period of time to intensify the flavour. If the mixture becomes dry, add 1 tablespoon of water and stir. Keeping the lid on the pan will help to keep the pork moist if you plan to simmer for a longer period of time.