Suggestions for the best southern sweet tea?

Get a loose leaf variety. Tea bags use lower quality tea. My grandmother made an iced earl grey and it was so good, I didn't need sugar. Just a lemon wedge and it was delicious.

Aight, there's a few ways to go about it.

The typical thing to start with is your brand. If you're going to be making big batches, you default to Lipton and Luzianne for southern sweet tea. However, Tetley does just fine. That's the stuff you're going to find in pretty much any grocery store. Luzianne and Tetley both do blends specifically for iced tea, and it does make a difference.

The next big thing is brew time. There's two ways to get strength without bitterness. The first is to go with a drip coffee maker. No bullshit. You will need to add an extra bag to keep the strength right, but the brew is so fast that you never get much bitterness at all.

If you don't want to do that, a boiling pot of water is your best bet. The size doesn't matter much, but it's a lot easier with a 3 or 4 quart pot. You bring it to a boil, drop the bags in, then cut the heat and steep for approximately five minutes, or until the tea is at the darkness you prefer.

Both of those will give you plenty of that deep strength that's the main characteristic of southern style sweet tea.

Iirc, all three of those brands make decaf black tea. Not that it matters much; even strong tea is lower caffeine than weak coffee. I'm sensitive to caffeine; it throws me into this weird panic state, and I don't get it from tea unless I'm basically guzzling the stuff. But the option is out there.

Now, if you're doing smaller batches, say a quart or half gallon, you can be a little more free with your tea choices because you don't have to worry as much about price or availability of larger amounts. Irish breakfast tea makes amazing iced tea, as does earl grey. English breakfast does a decent iced, but not as good as those two imo. Same basic idea, you either drip, or you boil and steep. All of those have plenty of decaf options for sure.

It really isn't about the bags tbh. It tends to be more about the tea itself. A lot of the teas that are sold in bigger amounts are shitty tea that's crumbled to dust. While you do get some of that in the name brands that make versions for iced tea, it's still better than the off brands or generics. But if you go with something like Taylor's, or Twinings, even their bagged teas are a better grade than most.

The cheaper the tea, the easier you have to be with it. Shorter steeps gives less bitterness than lower temps imo. I've never had great luck with cold brews or sun tea. They just sit too long before you get good strength, which means they're bitter.

I know nothing about southern sweet tea, but here are few things I know:
If the tea leaves are broken, like in tea bags, the tea will get bitter more easily. Try getting some good quality whole leaf tea.
There is no such thing as low caffeine tea. Only less tea. Some brands/producers might make claims about the caffeine content of their tea, but as far as I know, there is no way to grow low caffeine tea.
Tea contains considerable amount of oxalates. If you or someone in your family has problems with kidney stones, you might want to keep your daily tea intake within safe limits.

One thing you might want to try is grandpa style brewing. Grandpa style brewing means, you put some tea leaves in a big mug or bottle and you keep refilling it with water as you drink from it. Many kinds of teas (green, white, black, etc.) can work for this type of brewing, but you might need to use less leaves as you would when brewing some other way.

I am not southern, so take what I say with that in mind. As for the tea, I like to use Celestial Seasonings’ Caffeine Free Herbal Tea with Roasted Chicory. It is naturally caffeine free, but it is also not “tea”.

Before I started using that I used Alton Brown’s recipe. The one I used to use called for Lipton tea bags (from what I recall, it has been over a decade).

I like green tea

Depends on if you are after the caffeine or a cool, refreshing drink. Most decent herbal teas ice up very well. Adding one to regular Ceylon tea can sweeten it up depending on what you picked.

Personally we use Pukka but there are others. Don’t want to drop any links as the more generic ones were all Amazon but a quick search should get you going.