To keep fruit from being icy in ice cream you can macerate the fruit with sugar or pre cook the fruit or even puree the fruit before adding it to the ice cream which can reduce the amount of free water in the fruit which can freeze into ice crystals in the ice cream.
Cooking the fruit reduces the water content and makes it less prone to freezing in ice cream.
Cooking the fruit also intensifies the fruit's flavor, which can also be beneficial when it's added to the ice cream.
And cooking the fruit also softens the texture of the fruit and makes it blend into the ice cream more easily.
You can gently saute or roast the fruit with a touch of some lemon juice or salt before you cool the fruit and add it to the ice cream.
Macerating the fruit with sugar also helps to prevent the fruit from being icy in the ice cream by drawing out excess moisture and reducing the amount of water that can freeze in the fruit.
The sugar that you macerate the fruit with also creates a syrup and further prevents the fruit from freezing into ice chunks in the ice cream.
To macerate the fruit with sugar, mix the chopped fruit with some sugar and allow it to sit for awhile.
Then after you allow the fruit with the sugar to sit for awhile, you can then drain off any excess liquid before you add it to your ice cream.