In a medium bowl, whisk together the sweetened condensed milk and cold water until well combined. Slowly stir in the instant vanilla pudding mix, ensuring it is smooth and lump-free. Cover the mixture and refrigerate for at least 1 hour.

While the pudding sets, slice fresh peaches and heat them in a skillet over medium heat. Add the sugar, brown sugar, and fresh lemon juice, cooking for 2 minutes until the peaches soften. Sprinkle in the cornstarch, continuing to cook for an additional 5 minutes until thickened. Cool in the refrigerator.

In a separate mixing bowl, combine softened butter, brown sugar, sugar, flour, and cinnamon. Mix until it resembles coarse crumbs. Set aside.

Pour the heavy cream into the bowl of a stand mixer and beat on medium-high until stiff peaks form, about 3-5 minutes. Fold in the chilled pudding mixture.

In a large trifle bowl or individual cups, layer the pudding mixture, Nilla wafers, peach filling, and repeat until filled. Finish with whipped cream and crumble.

Cover with plastic wrap and refrigerate for 4-6 hours to soften the wafers and meld flavors.