In a large mixing bowl, whisk together the cold milk and instant pudding mix for about 2 minutes until smooth and thickened. Let the pudding sit for 5 minutes to fully set.
In another bowl, beat the softened cream cheese until completely smooth. Add the sweetened condensed milk, dulce de leche, vanilla extract, and kosher salt. Beat just until creamy and combined.
Gently fold the prepared pudding into the dulce de leche mixture using a rubber spatula until smooth.
In a chilled mixing bowl, whip the heavy cream and powdered sugar until stiff peaks form.
Fold the whipped cream into the pudding mixture in two additions until light and fluffy.
Spread a thin layer of pudding mixture onto the bottom of a 9x13-inch dish or trifle bowl.
Add a layer of vanilla wafers followed by sliced bananas.
Spread a generous layer of pudding mixture over the bananas. Repeat the layers until all ingredients are used, finishing with pudding on top.
Cover tightly and refrigerate for at least 6 hours or overnight.
Before serving, drizzle the top lightly with warmed dulce de leche and garnish with whipped cream and crushed vanilla wafers.