Peel and cut potatoes into 1-inch chunks.
Boil potatoes in well-salted water until just tender, 12–15 minutes.
Drain potatoes, spread on a sheet pan, and let steam-dry until warm.
Simmer eggs for 10 minutes, chill in ice water, then peel and chop.
Whisk mayonnaise, mustard, vinegar, sugar, salt, pepper, and celery seed in a large bowl.
Fold in celery, red onion, relish, and dill until evenly coated.
Gently add warm potatoes and chopped eggs; toss to coat without mashing.
Cover and chill at least 1 hour to meld flavors. Adjust seasoning to taste.
Dust with paprika just before serving.