Giant amounts of high-fructose corn syrup are proven to have bizarre, long-term health effects on most vital organs, that is a fact. The reason it's harmless when you eat fruit is that the physical structure of fruit fibers actually prevents your intestines from absorbing the majority of the fructose; you taste the fructose in your mouth, but your body absorbs very little of it. When you're thirsty, do what I do: have a massive vessel of condensation-dripping icewater next to you at all times. Very refreshing. And when I'm feeling really bold, I squeeze a tiny spurt of lemon juice into my icy water slush.
Let me tell you a true anecdote: back in 2016 I had a blood test in the Dr. office and most of my cholesterol levels were perfectly normal except my highly elevated triglycerides (which in itself doesn't cause heart disease, but they can cause build up of bad cholesterols that do cause heart disease). It didn't take me much Internet homework to learn that HFCS is the ultimate triglyceride bogeyman villain. So I completely quit soft drinks rights then and there forever. Then only a few months later I had another blood test and my triglyceride levels were cut in HALF, almost back down to a normal level. And my only lifestyle difference was my lack of daily soft drinks. At the very least, it's food for thought.
When thirsty, drink icewater, not soda. I can't stress that enough.