Create / modify soft drink recipe

This is a basic recipe for a soft drink containing coffee cherry tea: water, coffee cherry tea, grape juice, lemon juice, carbonic acid Unfortunately it doesn't taste that good. Your task is to make the drink tasty and refreshing. It should not contain additional sugar or sugar substitutes (the latter only if there is no other way). If you use any flavorings, please tell me where i can buy them in germany in small amounts. The recipe must contain coffee cherry tea, water and carbonic acid. Send me three clearly different recipes to fulfill the task. And of course there's no accounting for taste.