Cook the pasta: Bring a large pot of salted water to a boil. Add macaroni and cook until just al dente, 1–2 minutes less than package directions.
You want it tender but not soft.
Chill it fast: Drain and rinse the pasta under cold water to stop cooking. Shake off excess water and spread on a sheet pan to cool for 5 minutes. This helps it keep its shape and prevents sogginess.
Make the dressing: In a large bowl, whisk together ranch, mayonnaise, Greek yogurt, Buffalo sauce, pickle brine (or vinegar), garlic powder, smoked paprika, a pinch of salt, and a few grinds of pepper.
Taste and adjust heat with more Buffalo sauce as needed.
Add the crunch: Stir in celery, red bell pepper, red onion, shredded carrots, green onions, and herbs. If using chicken, fold it in now.
Combine: Add the cooled macaroni and cheddar to the bowl. Toss gently until everything is evenly coated.
If it looks thick, splash in 1–2 tablespoons of water or milk to loosen the dressing.
Chill to marry flavors: Cover and refrigerate for at least 30 minutes, or up to 24 hours. The pasta will absorb some dressing as it rests.
Finish and serve: Before serving, stir and taste again. Add a little more ranch or Buffalo sauce if it feels dry, and adjust salt and pepper.
Top with crumbled blue cheese if you like. Serve cool or at room temperature.