I have never had a Sparkling Ice before but you have peaked my interest as I do not enjoy the taste of carbonated water either and although my seltzer came out pretty good, I only drank 1 and gave away the other 47ish bottles of it and they enjoyed it haha.
I looked up the ingredients of a Sparkling Ice to see what things could change the flavor to be less of a "CO2" flavor compared to a seltzer and I am wondering if maybe the different vitamins added will mitigate some of the carbonated water taste.
Blue Raspberry - Sparkling Ice Ingredients:
Carbonated Water, Natural Flavors, Citric Acid, Malic Acid, Potassium Benzoate (To Ensure Freshness), Fruit Juice (For Color), Sucralose, Caffeine From Natural Sources, Gum Arabic, Green Tea Extract, Calcium Disodium Edta (To Protect Flavor), Ester Gum, Retinol (Vitamin A), Niacinamide (Vitamin B3), Calcium Pantothenate (Vitamin B5), Cholecalciferol (Vitamin D3), Biotin, Cyanocobalamin (Vitamin B12), Pyridoxine Hydrochloride (Vitamin B6).
So maybe finding some of these chemicals that make up the "vitamins" in this drink or any other Sparkling Ice could be the key. Also the fruit juice they added might have helped along with the green tea extract might have a small impact as well on the ending flavor. I presume these Sparkling Ice drinks have a slightly sweeter flavor than a seltzer so maybe make a seltzer but back sweeten it before racking or cold crash to curb fermentation so that it leaves a little sugar in there. My batch of Seltzer has virtually no sweetness to it and my FG was exactly 1.000 so there was virtually almost no sugar left in it.
Hope this tiny bit of info helps and I'd like to know how your batch turns out so that I could maybe reconsider my stance on brewing another seltzer in the future