Bring a large pot of salted water to a rolling boil. Add the dried elbow macaroni and cook according to package instructions, increasing the time by 2 minutes for a softer texture. Drain and rinse under cold running water until cool.

In a medium bowl, whisk together the mayonnaise, apple cider vinegar, sugar, sweet relish, and Dijon mustard. Add salt and pepper to taste.

In a mixing bowl, combine the cooled macaroni with the dressing. Add diced red bell pepper, chopped celery, diced red onion, and chopped hard-boiled eggs. Toss gently until well-coated.

Serve immediately or refrigerate for about 1 hour to enhance flavors. Toss before serving and adjust seasoning if necessary.