In a food processor crush graham crackers until they are fine crumbs. Then mix in melted butter.
Lightly grease the springform pan. Add crumb mixture into the pan and press it down on the bottom. When done, pop it in the freezer.
In food processor mix, vanilla, and cream cheese until smooth.
Then add the eggs and blend until smooth.
Mix in two cups of the sweetener and blend until fully mixed.
Dump 3/4 of mixture onto graham crust.
In processor mix the rest of the mixture with the other 1/2 cup sweetener and the blueberries and blend until smooth.
Dump the blueberry mixture on top of the other mix. Using a fork or knife, carefully swirl it around to slightly mix it together to give that marble look. Be really careful not to dig into the crust.
Place the trivet into the bottom of the inner pot of the Instant Pot. Then add one cup of water. Carefully put the pan inside the pot on the trivet.
When it beeps that it is done, open the valve to vent (quick pressure release).
Then remove the cheesecake from the pot and allow to cool on the counter for about 30-45 minutes. Then move to the fridge.
Do not remove from pan or slice until it is fully chilled. After chilled slice and serve with a few fresh blueberries.
If you are trying to reduce fat you can use one pack of regular cream cheese and one low-fat one. I have done that and it works well.
I would not use both packs of low-fat. It is a much softer cheese and will not hold shape and texture as well if you do both as low-fat.