How can I make my icecream soft as it is too hard to carve straight from the fridge?
If you really don't want to defrost it, you need to do something that will make it less hard when frozen. One choice, if it doesn't conflict with your allergies or your flavor profiles, would be to add alcohol - a liquor of your choice will make it freeze significantly less hard.

Another option would be to make it less susceptible to crystallization when refreezing, so that you can defrost it on the counter (or 20 seconds in the microwave). Try adding about 1/4 teaspoon of xanthan gum to a quart of ice cream base, that should reduce your crystallization problem a bit. You may need to reduce the agar a little to compensate. (I learned this from pastry chef Dana Cree).