Stir together graham cracker crumbs, melted butter, and sugar until the mixture looks like wet sand. Press firmly into the bottom of a 9x13 inch dish using the bottom of a measuring cup to create an even layer. Refrigerate while you make the filling.

Beat softened cream cheese and powdered sugar together until completely smooth and fluffy, about 2 minutes, scraping the bowl once. Add lemon zest and juice and beat until incorporated.

In a separate bowl, whip cold heavy cream to stiff peaks, about 3-4 minutes on medium-high speed. Gently fold half the whipped cream into the cream cheese mixture to lighten it, then fold in the remaining cream. Sprinkle the dry pudding mix over the top and fold just until no streaks remain - the mixture will thicken slightly.

Combine 1.5 cups blueberries, sugar, and cornstarch in a small saucepan. Cook over medium heat, mashing berries occasionally, until the mixture bubbles and thickens to a jam consistency, about 5-6 minutes. Let cool completely to room temperature.

Spread half the lemon cream mixture over the chilled crust. Dollop spoonfuls of the cooled blueberry compote across the surface and swirl gently with a knife. Scatter 1 cup fresh blueberries over the compote. Spread the remaining lemon cream on top, smoothing to the edges. Cover and refrigerate at least 4 hours or overnight until completely set.

Before serving, top with remaining 0.5 cup fresh blueberries and extra lemon zest if desired. Slice with a sharp knife, wiping clean between cuts for neat squares. Serve chilled.