Bring a large pot of heavily salted water to a rolling boil on your stovetop, drop in the elbow macaroni, and cook according to the package directions until it reaches a perfectly tender, slightly soft bite.

Strain the hot pasta into a large colander, then immediately blast the noodles under hard, ice-cold running water for 60 seconds, tossing continuously until every grain is cold to the core. This rapid flash-chill halts the cooking process instantly and washes away loose starches, ensuring a clean, separate texture that stays resilient over hours of storage.

Leave the colander in the sink to drain undisturbed for 10 minutes until the pasta is completely dry. While the macaroni dries, finely dice your celery stalks, red and green bell peppers, and red onion, aiming for uniform cuts that match the small size of the elbow noodles.

In a separate large mixing bowl, combine the mayonnaise, apple cider vinegar, granulated white sugar, yellow mustard, salt, and black pepper, whisking aggressively for 45 seconds until the sugar crystals dissolve and the dressing forms a smooth, opaque surfactant emulsion.

Dump the completely dry, chilled macaroni noodles, the finely chopped vegetables, and the well-drained sweet pickle relish directly into the bowl with the whipped dressing.

Use wide wooden spoons or kitchen tongs to gently fold the ingredients together from the bottom up until the crisp vegetables and relish are evenly speckled throughout the creamy pasta matrix. Cover the bowl tightly with plastic wrap and transfer it to the refrigerator for a minimum of 2 hours, allowing the flavors to meld and the starches to firm up to their signature snappy finish before serving.