Tempeh Buffalo “Wings”

Name: Tempeh Buffalo “Wings”
Ingredients: 1/2 c. vegan mayonnaise; 2 tbsp. chopped fresh dill; 1 tbsp. unsweetened almond milk, plus more if needed; 1 tbsp. apple cider vinegar; 1/4 tsp. garlic powder; 1/4 tsp. onion powder; Large pinch sweet paprika; Kosher salt; Freshly ground black pepper; 2 (8-ounce) blocks tempeh; 2 tbsp. safflower or vegetable oil, plus more for grill; 1/2 c. hot sauce (Frank's preferred); 1/2 c. vegan butter; 1 tbsp. light agave syrup; 4 celery stalks, cut into sticks, for serving