Mix almond flour, sucralose sweetener, butter, and cinnamon together in a large bowl. Press over the bottom and up the sides of a deep-dish pie plate to form a crust.
Bake in the preheated oven until crust is firm, about 7 minutes. Let cool completely.
Beat cream cheese in a bowl with an electric mixer until light and fluffy. Beat in sweetened condensed milk. Add lemon juice and 1 teaspoon lemon zest; beat until thoroughly blended. Pour filling into the cooled crust.
Refrigerate until filling is set, about 4 hours.
Spread whipped topping over lemon filling. Garnish with remaining 1 teaspoon lemon zest.