Boil peeled and cubed russet potatoes in a Dutch oven until tender, about 15–20 minutes after the water reaches a boil, and add salt as needed during cooking. Drain and cool completely so the salad stays creamy and not watery.

Chill the cooked potatoes until fully cooled, about 10–15 minutes at room temperature, then set aside while you mix the rest. This prevents the dressing from thinning when combined.

In a large bowl, combine cooled potatoes with chopped hard-boiled eggs, diced celery, finely diced onion, and sweet pickle relish. Mix just until everything is evenly distributed.

In a bowl, mix mayonnaise, yellow mustard, white vinegar, sugar, salt, and black pepper until smooth and well combined. Taste and adjust salt and pepper if needed.

Pour the dressing over the potato mixture and fold gently so the potato cubes hold their shape. Stir minimally to keep a classic, chunky texture.

Refrigerate at 40°F / 4°C for at least 2 hours, up to overnight, to let flavors blend. The salad will thicken slightly as it chills.

Before serving, garnish with paprika for a traditional look. Spoon into a serving bowl and serve cold.