Add half of the bacon to a large stock pot and heat over medium heat. Sweat until the fat is rendered (the bacon does not have to get dark), about 3 minutes. Add butter to the pot with the bacon and once melted, add in the onion, garlic, celery, celery root and a pinch of kosher salt. Cook until the vegetables have softened, about 5 minutes. Add chili paste and ¼ cup Hong Kong sauce and stir to coat. Add the rice wine and cook down until almost all of the liquid has been reduced, about 3-5 minutes more. Once reduced, add the potatoes, cream and chicken stock. Bring to a boil, then reduce to a gentle simmer over low heat. Cover and continue cooking, stirring occasionally, until the potatoes are mushy and beginning to fall apart, about 1 ½ - 2 hours. Meanwhile, add the remaining bacon to a large skillet. Heat over medium heat and cook until the bacon is browned and crispy on both sides, about 8-10 minutes. Remove to a paper towel-lined plate to cool. Using an immersion blender, purée the soup until smooth and creamy. Alternatively, blend the soup in batches using a regular blender. Add additional stock, as necessary, until soup reaches desired consistency. Season to taste with salt and additional Hong Kong, as desired. Serve warm, topped with sliced scallions and crumbled bacon bits.