Preheat oven to 325°F (163°C) and wrap the outside of a 9-inch springform pan with two layers of aluminum foil.
In a medium bowl, combine graham cracker crumbs, sugar, and cinnamon. Stir in melted butter until mixture resembles wet sand. Press firmly into the bottom of the prepared pan. Bake for 10 minutes, then set aside to cool.
In a medium saucepan over medium heat, combine diced apples, brown sugar, cinnamon, nutmeg, lemon juice, and butter. Cook for 6-8 minutes until apples soften. Stir in cornstarch slurry and cook for 1 more minute until thickened. Let cool completely.
In a bowl, whisk together flour, oats, brown sugar, cinnamon, and salt. Cut in cold butter until pea-sized clumps form. Spread on a parchment-lined baking sheet and bake at 325°F for 12-15 minutes until golden. Let cool completely.
In a stand mixer, beat softened cream cheese on medium speed until smooth. Add sugar, sour cream, vanilla, cornstarch, and cinnamon, mixing until combined. Add eggs one at a time on low speed, mixing just until incorporated.
Spread the cooled apple filling over the cooled crust. Pour the cheesecake batter over the apples and smooth the top. Tap the pan gently to release air bubbles.
Place the foil-wrapped springform pan in a roasting pan and add hot water to reach about an inch up the sides. Bake at 325°F for 55-65 minutes, until the edges are set and the center has a gentle jiggle.
Turn off the oven, crack the door open, and let the cheesecake cool inside for 1 hour. Remove from the water bath and let cool completely at room temperature.
Refrigerate the cheesecake uncovered for at least 4 hours or overnight. Before serving, release the springform ring, sprinkle with the baked crumble, and drizzle with salted caramel sauce.