Take any ice cream recipe, sub 3/4 the sugar for Allulose, and the rest with splenda/sucralose.
Took me 12 batches and 4 different artificial sweeteners to figure this out, allulose is the only way to make sure it's creamy and ice crystals don't form, and that it doesnt turn into a rock in the freezer. Erythritol also can work (I'm apparently allergic to it so I haven't experimented much) but the aftertaste is evident and takes away from it imo. However, it's much easier to find than allulose.
If you want to add something like caramel sauce or cake batter or hot fudge to the ice cream, do the same thing. Make your own and sub out the sugar for allulose and splenda.
Neither allulose nor sucralose raise blood sugar, but allulose does have calories, albeit far fewer than sugar. All the store "sugar free" ice cream uses sugar alcohols that raise blood sugar, which doesn't work for people with conditions like diabetes.
I used to do Keto, and I remember having realy good MCT oil vegan coffee creamer. Thick and creamy.
Maybe try using that powder mixed with Allulose or Bochasweet?