Blue Cheese Horseradish Dressing

1 (16 ounce) jar mayonnaise (such as Hellmann's®/Best Foods®)

10 ounces sour cream

6 tablespoons milk

1 (4 ounce) package crumbled blue cheese

or more to taste

1 dash hot pepper sauce

⅛ teaspoon prepared horseradish

⅛ teaspoon garlic powder

or to taste