Preheat oven to 350°F. Grease or line a 9×5-inch loaf pan.
Whisk 1½ cups flour, 2 teaspoons baking powder, and ½ teaspoon salt together.
In a large bowl, combine ¾ cup Greek yogurt, ½ cup melted butter, ½ cup sugar, ¼ cup brown sugar, 2 eggs, 1 teaspoon vanilla, 1 tablespoon lemon zest, and ¼ cup lemon juice.
Gently fold the dry ingredients into the wet ingredients until just combined.
Toss 1½ cups blueberries with the remaining 1 tablespoon flour and gently fold them into the batter.
Pour into the prepared pan.
Bake at 350°F for 45–55 minutes, checking around 40 minutes.
Cool in the pan for 15 minutes, then transfer to a wire rack and cool completely.
Whisk ¾ cup powdered sugar, ½ teaspoon lemon zest, and 2 tablespoons milk together. Add up to 1 additional tablespoon milk until you reach your desired consistency.