Prepare the pan: Line the bottom of an 8- or 9-inch springform pan with parchment paper. Lightly mist the sides with nonstick spray for easy release.
Make the crust: In a bowl, combine graham crumbs, sweetener, and melted light butter.
Mix until the crumbs are evenly moistened. If the mixture looks dry and sandy, add 1–2 tablespoons water. It should clump when pressed.
Press and chill: Firmly press the crumb mixture into the pan, going slightly up the sides.
Use the bottom of a measuring cup to compact it well. Chill in the fridge while you make the filling.
Bloom the gelatin: In a small bowl, sprinkle gelatin over 1/4 cup cold water. Let it sit for 5 minutes until it swells.
Dissolve the gelatin: Microwave the bloomed gelatin for 10–15 seconds until fully melted (or warm gently on the stove).
Do not boil. Let it cool for 2–3 minutes so it’s warm but not hot.
Beat the cream cheese: In a large bowl, beat softened reduced-fat cream cheese with an electric mixer until smooth and lump-free.
Add flavor and sweetness: Mix in Greek yogurt, vanilla, lemon zest, powdered sweetener, and lemon juice. Beat until creamy and well combined, scraping the bowl as needed.
Incorporate the gelatin: With the mixer on low, slowly stream in the melted gelatin.
Mix until fully blended. The filling will thicken slightly as it sits.
Fill the crust: Pour the mixture over the chilled crust and smooth the top with an offset spatula. Gently tap the pan on the counter to release air bubbles.
Chill to set: Cover and refrigerate for at least 4 hours, ideally overnight, until firm enough to slice cleanly.
Unmold and finish: Run a thin knife around the edge before releasing the springform.
Top with berries or a light fruit sauce just before serving.