Preheat the oven to 400 degrees F (200 degrees C). Line 2 baking sheets with parchment paper and set aside.

Combine flour, sugar, baking powder, lemon zest, salt, and baking soda in the bowl of a food processor. Pulse 3 or 4 times to mix. Add butter and pulse until mixture resembles coarse crumbs, 20 to 25 times. Pour mixture into a large bowl. Fold in blueberries, making sure they are well coated with the dry ingredients.

Beat 1/2 cup heavy cream, egg, and lemon juice together using a fork in a small bowl. Stir into flour mixture and mix just until slightly moistened.

Turn dough out onto a well floured surface. Gather dough in a circle using floured hands, kneading only slightly to incorporate any remaining dry ingredients. Flatten dough into a 9-inch round disc; cut disc into 8 triangles. Transfer scones using a bench scraper to the prepared baking sheets (4 scones per baking sheet). Brush scones with 2 tablespoons heavy cream.

Bake in the preheated oven until light brown, 20 to 23 minutes. Remove from the oven and let cool completely, about 30 minutes.

Mix powdered sugar and lemon juice together in a small bowl. Transfer to a small resealable plastic bag; snip the corner off of the bag using scissors, and drizzle cooled scones with glaze.