Prep the wings: Pat the wings completely dry with paper towels.
This helps the skin crisp later. Sprinkle with salt, pepper, garlic powder, onion powder, and smoked paprika. Toss to coat evenly.
Mix the sauce: In a bowl, whisk together the buffalo sauce and ranch dressing.
If using, melt the butter and whisk it in, then add the apple cider vinegar. Taste and adjust heat by adding more buffalo or ranch.
Load the crockpot: Place the seasoned wings in the slow cooker. Pour about two-thirds of the sauce over the wings and toss lightly to coat.
Reserve the remaining sauce for finishing.
Slow cook: Cover and cook on Low for 3.5–4.5 hours or on High for 2–2.5 hours. The wings should be tender but not falling apart.
Preheat the broiler: Line a large sheet pan with foil and set a wire rack on top, if you have one. This helps air circulate for better crisping.
Preheat your oven broiler to high.
Broil to crisp: Using tongs, transfer wings to the rack, letting excess liquid drip off. Broil for 4–6 minutes per side, until the skin is browned and crisp at the edges. Watch closely to avoid burning.
Sauce and serve: Toss the hot wings with the reserved sauce.
Sprinkle with chopped parsley or chives. Serve right away with celery sticks and extra ranch if you like.