So to make the ground venison patty, I usually take a pound of venison and cut in another pound of ground pork. Add 1/4 cup panko, one egg, 2 tbs fish sauce, 1 tbs soy, 1 tbs honey, 2 teaspoons ground coriander, 3 cloves of garlic diced, juice from 1 lime, and a 1" piece of graded ginger or galangal. You can feel free to add some Thai chilies or birds eye chilies if you want if you like some heat. Mix with your hands and form a patty. You can cook out on the bbq but keep an eye on it for flair ups because of the pork fat. And remember to fully cook it though because of the pork.
Another option if you have some venison trim and not ground venison. Is to marinade it in fish sauce, sugar, lemongrass and shallots overnight. Then braise it in coconut water until its tender, about 2 hours. And use that cubed meat in the Banh Mi.
The night before you need to pickle the daikon and carrots. Just heat 1 cup white vinegar and 1 cup sugar and 1 tbs salt until dissolved and pickle the veggies.
To assemble make some siracha mayo and spread on baguette, place patty, then pickled daikon and carrots, fresh cucumber, fresh cilantro, thinly sliced jalapeño, and a drizzle of soy.