In a mixing bowl, whisk together Greek yogurt, buttermilk, and mayonnaise until smooth. Add minced garlic, lemon juice, poppy seeds, parsley, dill, onion powder, paprika, salt, and pepper. Chill for at least 30 minutes.

In a large bowl, add spinach, chopped broccoli, sliced avocado, and blueberries.

Sprinkle in feta cheese, cranberries, and sunflower seeds. Gently toss together.

Drizzle the dressing over the salad and toss gently to combine without mashing the ingredients.

Serve immediately for best flavor and texture.