Loaded Potato Soup

* 4 slices bacon, diced
* 2 tablespoons unsalted butter
* 1 small onion, finely chopped
* 2 celery stalks, finely chopped
* 2 tablespoons all-purpose flour
* 4 cups chicken stock
* 1 cup whole milk
* 1 cup heavy cream
* 4 russet potatoes, peeled and diced into 1/2-inch cubes
* 1 teaspoon paprika
* 1 teaspoon chicken bouillon powder
* Salt and freshly pepper, to taste
* 2 cups Tillamook cheddar cheese, shredded (divided)
* For topping: sliced scallions, sour cream, extra cheddar