A suggestion...you are in a hot climate....and I KNOW I love diet soda on hot days....I’ve found a substitute....an organic lemonade (or even a lemon squeezed into a glass) up to 1 inch per glass...add ice, and seltzer/sparkling water....to give it fizz. It satisfies me MOST of the time.
Yeah, we just bought a bag of lemons for about $2 at a discount supermarket to do something like that. The doctor ordered me off of diet soda saying it was actually worse than regular sugared soda.