Lightly coat a 7x3-inch springform pan with nonstick spray and set aside.
Add all the crust ingredients to a large bowl and stir until well combined.
Press the mixture into the prepared springform pan.
Press the crust and try to line the sides about to the middle of the pan edges.
Freeze for at least 20 minutes.
Make the filling:
Add cream cheese and erythritol to a large bowl. Use a hand mixer to beat on low speed until well-mixed.
Add heavy cream, sour cream, lemon juice, lemon zest, and vanilla extract. Beat on low speed until smooth, about 30 seconds. Stop to scrape the sides and bottom of the bowl.
On low speed, add the eggs one at a time, beating until just combined, careful to not overmix.
Pour the batter over the crust, and flatten the top with a spatula.
Place the metal trivet into a 6-qt Instant Pot and add 1 1/2 cups water.
Gently transfer the cheesecake pan on top of the trivet.
Select manual setting and adjust the pressure to high. Set time to 30 minutes.
When finished cooking and the Instant Pot beeps, release pressure naturally for about 20-30 minutes. Manually release any remaining pressure by gradually turning the release knob to its venting position.
Carefully open the pot and transfer cheesecake to a cooling rack. The cheesecake should be jiggly, but not liquidy.
Let it cool for 1 hour, after which run a paring knife around the edges.
Transfer cheesecake to the refrigerator for at least 12 hours or overnight.
Beat heavy cream, erythritol, and vanilla until stiff peaks form. Pipe on the cheesecake, garnish with blueberries and a few strawberries in the center.
Carefully remove the chilled cheesecake from the pan. Peel off the parchment paper. Slice and serve.