Grease two 9x5-inch loaf pans. Line with parchment paper overhang, if desired. Set aside.
In a small bowl, whisk together sugar, brown sugar, cinnamon, and salt. Set aside.
Punch down risen dough. Divide into two equal pieces. Keep one dough covered while you work with other dough.
Transfer dough to a lightly floured work surface. Roll dough out to a 12x16-inch rectangle. Sprinkle half of cinnamon sugar mixture over surface of dough. Sprinkle 3/4 cup frozen blueberries over sugar.
Starting at the long end of rectangle, roll dough into a tight log. Pinch seams together and place log seam-side down on work surface. Use a sharp knife to slice log in half lengthwise. Pinch cut seams shut.
Stretch each log to a length of about 8-inch. Twist the two logs of dough over each other to form a spiral or braid. Pinch ends together and place in one of the prepared bread loaf pans. Cover with plastic wrap and allow dough to rest at room temperature for 30 minutes until dough as puffed up.
Repeat steps with remaining dough.
Preheat oven to 350 degrees F. Remove covers from bread pan. Bake bread for 38-40 minutes until golden brown on top and internal temperature of bread registers at least 185 degrees F. Rotate bread pans midway through baking. If bread is browning too fast, cover with foil to prevent bread from burning. Allow bread to remain in pan for 10 minutes after baking. Loosen bread from bread pan and unmold. Allow bread to cool on wire rack. Use a serrated bread knife to slice bread once cooled.