In a small saucepan combine blueberries, lemon juice, sugar & cinnamon. Bring to a simmer over medium-high heat, mashing the berries with the back of a spoon. Simmer for 5 minutes.
Mix together cornstarch & cold water. Add to blueberry sauce and heat until thickened, about a minute. Transfer sauce to a bowl and cool completely.
In a metal bowl using a stand or hand mixer, whip heavy cream until stiff peaks.
In a separate bowl, mix together sweetened condensed milk, cream cheese & vanilla (a few chunks of cream cheese are ok).
Slowly fold in whipped cream with cream cheese mixture until no white streaks remain.
Line a standard loaf pan with parchment paper. Scoop ⅓ of ice cream mixture into the bottom of the loaf pan. Dot with ⅓ of blueberry sauce and ⅓ of graham cracker chunks.
Repeat this process with 2 more layers of ice cream mixture, blueberry sauce and graham cracker chunks. Using a butter knife swirl mixture in the pan making sure to reach to the bottom.
Cover tightly with plastic wrap and freeze for at least 6 hours.
To serve: remove from freezer for 10 minutes before scooping.