In a medium bowl, combine the fresh blueberries, 1/4 cup of granulated sugar, lemon juice, and vanilla extract. Gently toss to coat the blueberries and set aside to macerate for about 15 minutes.
In a large mixing bowl, beat the softened cream cheese with the remaining 3/4 cup of granulated sugar until smooth and creamy.
In another bowl, whip the heavy cream with the powdered sugar and lemon zest until soft peaks form.
Gently fold the whipped cream into the cream cheese mixture until fully combined and smooth.
In a trifle dish or individual serving glasses, layer half of the pound cake cubes at the bottom.
Spoon half of the cream cheese mixture over the cake, followed by half of the macerated blueberries. If using, add a layer of blueberry pie filling.
Repeat the layers with the remaining pound cake, cream cheese mixture, and blueberries.
Cover and refrigerate the trifle for at least 2 hours to allow the flavors to meld together.