I sorta had the same problem, not an addiction, i just liked sodas and didn’t work out. I starting lifting and taking better care of myself when i was about 20, that’s about the time redbull and some other energy drinks came out. I stopped drinking sodas and moved over to redbulls (not a good trade).
Took a few years till low carb energy drinks came out, soon as they did i switched over. Now at 28 i drink nothing but 1 low carb energy drink in the morning, milk, and water through the day. Never felt better.
If you can handle stevia, get the flavored liquid version that comes in a dropper. Put as much as you like/can handle into some small club soda bottles. Tastes pretty good, but I personally can’t taste the stevia aftertaste.
Coffee is a good alternative. Has a lot of flavor, I can’t do tea because it’s too weak. It will help with the caffeine withdraws if there are any for you. I drink 1/3-1/2 gallon of milk a day, so having lots of milk (and stevia) in my coffee is a treat for me.
I have some friends that use flavored BCAAs in water. The apple flavor for Xtend is pretty good.
Try to make the transition as easy as you can so you can be consistent. With that said, do it as fast as possible. if you can last 3 solid weeks usually the habit is broken, anything after that is all in your head.