Begin by whisking 5 cups of flour, 1/4 cup of sugar, 1 tablespoon of baking powder, 1 teaspoon of baking soda, and 1 teaspoon of salt together in a large mixing bowl. Incorporate 1/2 cup of cold butter and 1/2 cup of shortening into the dry ingredients using a pastry blender or two forks, aiming for a texture that resembles coarse crumbs. In a separate, smaller bowl, dissolve 2 teaspoons of yeast in 1/4 cup of warm water and allow it to rest for about 5 minutes, or until it becomes frothy. Combine the frothy yeast mixture and 2 cups of buttermilk with the flour mixture, stirring until a dough forms. Transfer the dough onto a surface dusted with flour and knead it gently 3 to 4 times. Roll out the dough until it’s about 1-inch thick, then use a biscuit cutter to shape the biscuits. Arrange the biscuits on a baking sheet, cover them, and let them rise in a warm spot for about 30 minutes. Heat the oven to 400°F (200°C) in preparation for baking. Bake the biscuits for 15-20 minutes, or until they turn a golden brown color. Serve the biscuits warm and enjoy their delicious taste!