Might be a bit hard for you to buy depending on where you live but YABU energy drink is just straight up carbonated Polish apple juice with caffeine. I drank a few different flavours they have and they are nice.

You can get caffenated water; I'm sure it would carbonate just as well as regular water.

Hiball energy seltzer is pretty good, but they stopped selling it near me.

Dunno where you are, but ChariTea has a new sugar free mate. Mate based drinks in general tend to be at least less sweet than that energy drink stuff.

I personally usually just make coffee at home and take it with me, but I recognise that doesn't work for everyone.

Not to be that guy, but as someone who quit caffeine entirely, honestly it's kinda great not needing caffeine. I traded my daily coffee for water and now I just drink shitloads of water and it's honesty glorious. Waking up and just...going is amazing

Wanted to throw it out there because it seems not many people try to kick caffeine

I actually think Lipton peach ice tea in 2lt packets have no sugar added, giving them a really mild flavor compared to their fruit juice like flavor in canned and 1lt forms

Bawls is just guarana and caffeine iirc.

Ed: hfcs in it now I guess, shame

just fucking buy caffeine at this point.