There are professional weightlifters and strong men who are vegan, who are held to the same enhancment drug testing as the meat eating athletes. If you were not versed in food variety may be why you couldn’t hold your weight class. Coupled with you most likely being calorie deprieved because a balanced vegan diet is less calorie dense, so you would have to eat more. Soy, seeds, legumes, nut, and veg protein shakes with nut butters and oaks is basically it. Pastas on burnout days and repeat. I’ve been into fitness my whole life and I know plenty of vegan athletes who perform just fine.