Combine the vinegar, dill, paprika, sugar, mayonnaise, mustard, garlic, and celery. Mix well and set aside.

Wash the potatoes and place them in a large pot with enough water to cover them. Add salt and bring to a boil.

Reduce the heat and simmer until the potatoes are fork-tender but not falling apart.

Drain the potatoes and allow them to cool enough to handle.

Peel the potatoes, cut them into chunks, and set aside.

If using frozen peas and carrots, defrost them and drain well.

Chop the remaining vegetables and parsley.

Add the potatoes, mayonnaise mixture, peas and carrots, sweet corn, bell pepper, red onion, scallions, and half of the parsley to a large bowl. Gently combine until everything is evenly coated. Add more mayonnaise if needed, then season with salt and black pepper to taste.

Garnish with the remaining parsley.