Cut the pound cake or angel food cake into 1-inch cubes (about 8 cups total). Set aside while you prepare the lemon cream filling.
In a large mixing bowl, beat the softened cream cheese until smooth and creamy, about 2 minutes on medium speed. Add the powdered sugar, vanilla extract, lemon juice, and lemon zest. Mix until well combined and smooth.
Fold in the lemon curd gently until fully incorporated. The mixture should be thick but still spreadable.
In a separate chilled bowl, whip the cold heavy whipping cream until it forms stiff peaks, about 3 to 4 minutes on high speed. You want it thick enough to hold its shape but not over-whipped.
Gently fold about half of the whipped cream into the lemon cream mixture to lighten it up, then fold in the remaining whipped cream until fully incorporated.
Begin layering in a large trifle bowl or individual serving glasses. Start with a layer of cake cubes on the bottom. If using, brush or drizzle limoncello or lemon juice over the cake cubes.
Spread a generous layer of the lemon cream over the cake, then scatter fresh blueberries on top. If using, dollop small spoonfuls of blueberry preserves over the berries.
Repeat the layers: cake, lemon cream, blueberries, and preserves. For a large trifle bowl, layer everything three times. For smaller individual dishes, two layers should suffice.
Finish with a final layer of lemon cream on top. Cover the trifle and refrigerate for at least 2 hours, or up to 6 hours before serving.
Right before serving, top with remaining whipped cream, additional fresh blueberries, lemon slices, and mint leaves if desired. Serve chilled.