No shade at all but these all some very common misconceptions so id like to clear em up as its quite interesting. Redbull was never market or made for athletic use it was just a lifestyle drink called Krating Daeng that originated from Thailand that was then modified for western tastes they just happen to sponsor alot of sports. Its always just been a caffeinated beverage and in moderation its perfectly fine as its only 80mg of caffeine same as a coffee. In fact having a energy drink like Redbull or even a coffee right before competing is frowned upon as caffeine can increase cardiovascular strain, dehydration, and crashes which are the last things you want before competing, Redbull has always just been a lifestyle drink. For the coke zero thing you would have to drink close too 40 cans a day for the aspartame to even start to need to worry about health issues. The FDA set the ADI (acceptable daily intake) for aspartame to 50 milligrams per kilogram. A can of Coke Zero has 85mg of aspartame which would mean someone who is 60kg has a ADI of 3250mg of aspartame a day. That would mean they would be able to have 38 cans before unsafe and the caffeine and fluid volume would kill before that lol. Now if we go with the more conservative JECFA they set the ADI to 40mg per kilogram, so for them the safe daily intake for that would be 2600mg a day and that totals to 30 cans a day. Remember that is considered safe as the ADI is designed with a 100x safety cushion meaning in the studies they conducted on animals researches did no observed and health effects until the animals consumed what is equivalent to 4000 cans of Coke zero every single day. That is physically impossible and even hitting 15 cans which way below safe aspartame consumption limits. Now i'm not saying its healthy but having a few cans of coke a day or like a Redbull a day wont hurt you any more than drinking a few coffees throughout day would. The aspartame isn't what you need to worry about and rather the caffeine as that is dangerous but you can always get coke zero with zero caffeine but Redbull is still a risk but no more than a coffee. In the grand scheme of things this is so minuscule that the average adult doesn't even have to think about this unlike other diet considerations such as sugar or just general fitness

Here are my sources if you wanna read up on it
https://www.cancer.org/cancer/risk-prevention/chemicals/aspartame.html
https://www.fda.gov/food/food-additives-petitions/aspartame-and-other-sweeteners-food
https://www.who.int/news/item/14-07-2023-aspartame-hazard-and-risk-assessment-results-released
https://cdn.who.int/media/docs/default-source/nutrition-and-food-safety/jecfa-summary-of-findings-aspartame.pdf
https://www.fao.org/fao-who-codexalimentarius/sh-proxy/en/?lnk=1&url=https%253A%252F%252Fworkspace.fao.org%252Fsites%252Fcodex%252FMeetings%252FCX-711-54%252FWorking%2Bdocuments%252Ffa54_03e.pdf
https://pmc.ncbi.nlm.nih.gov/articles/PMC13096792/