I’ve had the same problem with most veggie burgers, but found a recipe years ago that really holds up. It’s a Jamaican Ital recipe: https://www.sun-sentinel.com/2005/05/26/bean-burgers-jamaica...
Coincidentally I just got back from Jamaica a few days ago, and as a vegetarian I always try to find the Rasta spot as soon as I can as they’re usually the ones with the best veg food. I was thinking of these burgers and now here we are — I guess I should make a batch this weekend!