Preheat oven to 350 degrees F (175 degrees C). Grease a fluted tube pan (such as Bundt®) with cooking spray.

Mix all-purpose flour, whole wheat flour, baking powder, salt, and baking soda together in a bowl.

Beat blueberry yogurt, brown sugar, 1 cup white sugar, egg substitute, lemon zest, and lecithin together in a large bowl until smooth. Fold in zucchini. Stir in flour mixture until just incorporated. Fold in blueberries very gently. Pour into the prepared tube pan.

Bake in the preheated oven until a toothpick inserted into the center comes out clean, 60 to 70 minutes. Let cool in the pan, 30 minutes. Invert cake onto a plate.

Combine 1/3 cup white sugar and lemon juice in a small saucepan over low heat; cook and stir until sugar dissolves and syrup is clear, 5 to 8 minutes.

Poke small holes all over the cake with a toothpick. Pour lemon syrup over the cake.