Adding meat is the best option

This is the best bun cha in SG and the closest thing to the one in Hanoi I had

The soup had proper smokiness from the well charred meats and the pork slices (or at least 30% of them) had the perfect bouncy slightly gelatinous bite. Unfortunately some of them were abit tough

Meatballs were good too, firm and crumbly and substantial

Worth a try