In a large bowl, combine the grated beetroot, diced cucumber, sliced radishes, chopped dill, and chopped chives.
In a separate bowl, whisk together buttermilk, plain yogurt, sour cream, vinegar, and sugar until well combined.
Pour the dressing over the vegetable mixture. Stir to combine and ensure all the vegetables are coated with the dressing.
Season with salt and pepper to taste.
Cover the bowl and refrigerate for at least 1-2 hours to allow the flavors to meld and the soup to chill.
Ladle the soup into bowls and garnish with sliced boiled eggs and, if desired, diced cooked potatoes.
Enjoy your meal!