Place the baked pie crust on a plate or pie board and have it ready. Weigh out 6 ounces of the hulled strawberries and set them aside; keep the remaining strawberries nearby.
Put the reserved 6 ounces of strawberries in a food processor and process until smooth, stopping to scrape down the bowl as needed. Transfer the puree to a measuring cup or bowl.
In a medium saucepan, whisk together the 3/4 cup sugar, 2 tablespoons cornstarch, 1 1/2 teaspoons Sure-Jell (low-sugar), and a pinch of salt until evenly combined.
Stir the strawberry puree into the dry mixture in the saucepan. Cook over medium-high heat, stirring constantly with a heatproof spatula, and bring the mixture to a full rolling boil.
Once boiling, continue to boil and stir, scraping the bottom and sides of the pan, for a full 2 minutes to thicken the glaze. Remove the pan from the heat.
Transfer the glaze to a large bowl and stir in the 1 tablespoon lemon juice. Let the glaze cool to room temperature before proceeding.
From the remaining hulled strawberries (3 pounds minus the 6 ounces you pureed), weigh out 2 pounds of the best-looking berries. Cut larger berries in half or quarters so pieces are uniform; leave small berries whole.
Add the prepared berries to the cooled glaze and gently toss until the berries are evenly coated.
Pile the glazed berries into the baked pie crust, arranging cut sides down as desired for presentation.
Refrigerate the pie until fully chilled and the filling has set, about 2 hours. Top with sweetened whipped cream if desired before serving.