Preheat the oven to 325°F and line an 8x8 inch baking pan with parchment paper, leaving overhang on two sides to lift the bars out later.
In a medium mixing bowl whisk together the almond flour, granulated sweetener, and salt for the crust until well combined.
Stir the melted butter and vanilla extract into the dry crust ingredients until the mixture is evenly moistened and resembles soft, slightly crumbly dough.
Transfer the crust mixture to the prepared pan and press it firmly and evenly into the bottom using clean hands or the bottom of a measuring cup to create a compact, even layer.
Bake the crust for 10 to 12 minutes until lightly golden at the edges, then set the pan on a cooling rack while you prepare the filling and reduce the oven temperature to 300°F if it has risen above that temperature.
In a large mixing bowl beat the softened cream cheese with a hand mixer on medium speed until completely smooth and fluffy, scraping down the sides of the bowl as needed.
Add the granulated sweetener to the cream cheese and beat again until well incorporated and no graininess remains.
Mix in the sour cream, vanilla extract, lemon juice, and salt until the mixture is smooth and creamy.
Add the eggs one at a time, beating on low speed just until each egg is incorporated and stopping to scrape the bowl, taking care not to overmix to avoid incorporating too much air.
Pour the cheesecake filling over the parbaked crust, smoothing the top with a spatula to create an even layer.
Bake the cheesecake bars at 300°F for 18 to 22 minutes until the edges are set and the center still has a slight jiggle when the pan is gently shaken.
Turn off the oven, crack the door open slightly, and let the pan sit in the warm oven for 15 minutes to help prevent cracking, then transfer the pan to a cooling rack and cool completely to room temperature.
While the cheesecake cools, place 1 cup of the chopped strawberries in a small saucepan with the powdered sweetener and lemon juice and cook over medium heat, stirring occasionally, until the berries release their juices and the mixture is bubbling and slightly thickened, about 5 to 7 minutes.
If using gelatin, sprinkle it over the water in a small bowl and let it sit for a few minutes to bloom, then stir the bloomed gelatin into the warm strawberry mixture until dissolved.
Remove the strawberry mixture from the heat, stir in the remaining 1/2 cup chopped fresh strawberries, and let the topping cool to room temperature so it is no longer warm to the touch.
Once the cheesecake layer has cooled to room temperature, gently spoon the cooled strawberry topping over the surface and spread it into an even layer without disturbing the cheesecake.
Cover the pan and refrigerate the bars for at least 3 hours, preferably overnight, until fully chilled and set for clean slicing.
When ready to serve, use the parchment overhang to lift the chilled cheesecake slab out of the pan, place it on a cutting board, and cut into 16 bars with a sharp knife, wiping the blade between cuts for neat slices.