I think this bears repeating. Switching to a different flavored soda probably won’t help your acid reflux.
Maybe try a smoothie or a slushie for a lunch drink? Just to mix it up a little so the water doesn’t seem so monotonous. They’re loaded with calories so you’ll want to adjust for that but the cold in your stomach might feel good.
How about an herbal tea, say lemon zinger (lemon with hibiscus blossom), iced down?
I’m fond of great big glasses of instant iced tea mix. Decaf and diet.
Usually in 24 ounce glasses, room temp. Sometimes in a mug, hot.
Yeah, the flavor isn’t absolutely top notch. (Darjeeling, it ain’t.) But it’s liquid, tastes okay, and keeps ya going to the bathroom all night…