I've been drinking iced tea exclusively for about 20 years.
I have a 1-gallon pitcher I make it in. For 1 gal I put in 4 or 5 bags of crap (like lipton or red rose) and either 2 bags of Earl Grey, or 1 bag of double bergamot and an additional bag of low-end.
I drink it unsweetened a lot. But if you want to sweeten then add 1/2 cup sugar and 1 Tbsp of lemon juice concentrate.
1/2 cup of granulated sugar in a gallon of tea is plenty, and it's nowhere near what you get in a gallon of soda.
ETA one liter of Coke has 108 grams of sugar in it.
There are 190 grams of sugar per cup.
Roughly 4 liters per gallon means a gallon of Coke has > 400 grams sugar, while my tea has 95 grams in it.