Preheat your oven to 325°F (160°C) and prepare a 9-inch springform pan by greasing it lightly.
In a mixing bowl, combine the almond flour, old-fashioned oats, melted coconut oil, maple syrup, cinnamon, and salt. Stir until the mixture is well combined and resembles damp sand.
Press the crust mixture evenly into the bottom of the prepared springform pan. Bake for 10-12 minutes or until lightly golden. Remove from the oven and allow it to cool slightly.
In a large mixing bowl, beat the room temperature cream cheese until smooth and creamy. Add the Greek yogurt, maple syrup (or honey), vanilla extract, cornstarch, lemon juice, and salt. Mix until fully combined and smooth.
Pour the cheesecake filling over the cooled crust, spreading it evenly. Tap the pan gently on the counter to release any air bubbles.
Bake the cheesecake for 30-35 minutes or until the edges are set but the center has a slight jiggle. Turn off the oven and crack open the oven door, allowing the cheesecake to cool down gradually for about an hour.
Once cooled, refrigerate the cheesecake for at least 4 hours, or preferably overnight, to let it set completely.
Before serving, toss the mixed berries with maple syrup and lemon juice in a bowl. Top the chilled cheesecake with the berry mixture, spreading it evenly.