Do you refreeze this after mixing in the additional ingredients? The picture looks like you should

I can see where this ice cream has a really interesting flavor profile. Here’s what I would do: I’d bloom the saffron in a tablespoon or so of room temperature heavy cream (not boiling water). I’d soften (but not melt) the ice cream, and stir in the saffron cream mixture and the rosewater to taste. I’d also fold in the pistachios. Then I’d pack the whole think back into the container and put a layer of wax paper or parchment flat against the surface of the now pretty soft ice cream, cover it, and freeze it for several hours. I hope this works for you.