Cook corn syrup, brown sugar, eggs, butter, vanilla, and salt in a saucepan over medium heat, stirring frequently, until thickened and glossy, 10 to 12 minutes. Stir in pecans and cool completely.
Mix graham cracker crumbs, sugar, melted butter, and salt until it holds together like wet sand. Press firmly into a 9x13 pan and refrigerate 15 minutes.
Beat cream cheese, powdered sugar, and vanilla until smooth. Fold in 1 cup whipped topping. Spread over the chilled crust. Refrigerate 20 minutes.
Pour the fully cooled pecan topping over the cream cheese layer and spread gently from the center outward.
Garnish with remaining whipped topping if desired. Cover and refrigerate at least 4 hours or overnight before slicing.