Make the crust: In a large bowl, whisk together flour, salt, and sugar. Cut in the cold butter until it resembles coarse crumbs. Stir in the sourdough discard and vinegar. Form into a disc, wrap, and chill for at least 1 hour.
Blind bake the crust: Preheat oven to 375°F (190°C). Roll out the chilled dough, place into a 9-inch pie dish, trim and crimp the edges. Dock the base with a fork. Line with parchment and add pie weights. Bake for 15 minutes, remove weights, then bake for another 10–15 minutes until golden. Cool completely.
Make the cream cheese filling: In a medium bowl, mix the whipped cream cheese, powdered sugar, and heavy cream until smooth. Spread into the cooled crust. Refrigerate while preparing the topping.
Make the strawberry topping: In a small saucepan, add 1 cup of strawberries, water, sugar, and cornstarch. Cook over medium heat, stirring, until thickened and glossy (about 5–7 minutes). Let cool slightly, then stir in remaining strawberries.
Assemble the pie: Spoon the cooled topping over the cream cheese layer. Smooth the top and refrigerate for at least 2 hours before slicing.