Add 8 ounces heavy whipping cream to a medium mixing bowl. Beat on high with a hand mixer (or stand mixer) until stiff peaks form. Set aside.
In a large mixing bowl, beat 4 ounces cream cheese until light and fluffy, about 2 minutes. Add 3 1/2 tablespoons lemon curd and mix to combine. Add the whipped cream and fold in with a rubber spatula until well mixed.
Add 1 1/2 cups strawberries, 1 1/2 cups raspberries, 1 1/2 cups blueberries, and 1 1/2 cups blackberries to a colander and rinse. Dry completely on paper towels, then remove stems and chop large berries as needed. I quarter the strawberries.
Add the dried berries and 2 cups mini marshmallows to the cream mixture. Fold gently with a spatula just until everything is coated.
Transfer to a serving bowl and top with a few more berries and marshmallows if desired. Enjoy immediately or chill in the refrigerator until ready to serve.