Lemon Blueberry Cheesecake Cake | Creamy, Tangy, Bakery-Style Bliss

2 cups fresh blueberries
⅓ cup sugar
1 tbsp cornstarch
1 tbsp lemon juice

For the creamy frosting:

8 oz cream cheese, softened
½ cup unsalted butter, softened
3 cups powdered sugar
1 tsp vanilla extract
1 tbsp lemon juice

For topping:

1 cup fresh blueberries
Thin lemon slices or zest for garnish