Line the bottom of a 9-inch springform pan with parchment paper and lightly grease the sides. Set aside on a flat surface.
Mix graham cracker crumbs, sugar, and melted butter until the mixture resembles wet sand, then press it firmly and evenly into the bottom of the prepared pan and about 1 inch up the sides. Refrigerate for at least 15 minutes.
Beat the softened cream cheese with a hand or stand mixer on medium speed for 2 to 3 minutes until completely smooth and fluffy, scraping down the sides as needed.
Sift the powdered sugar into the cream cheese, then add the vanilla extract and 2 tablespoons of lemon juice. Beat on medium-low until fully combined and silky smooth, about 1 minute.
In a separate clean bowl, beat the cold heavy cream on medium-high speed until stiff peaks form, about 3 to 4 minutes. Stop as soon as peaks hold firm — do not over-whip.
Gently fold the whipped cream into the cream cheese mixture in two to three additions using a rubber spatula, using slow sweeping motions until no white streaks remain. Do not stir vigorously.
Pour the filling over the chilled crust and use an offset spatula to spread it into an even, smooth layer. Tap the pan gently on the counter to release any air bubbles.
Cover loosely with plastic wrap and refrigerate for at least 4 hours, or overnight for the firmest, cleanest slices.
Cook half the strawberries with the sugar and 1 teaspoon lemon juice over medium heat for 4 to 5 minutes, then stir in the cornstarch-water slurry and cook 1 to 2 minutes more until thick and glossy. Cool completely, then stir in the remaining fresh strawberries.
Run a thin knife around the inside edge of the pan, remove the springform ring, spoon the cooled strawberry topping over the cheesecake, and slice with a hot, dry knife for the cleanest cuts.