The thing about citric acid sounds mainly like fearmongering tbh, it's just the acid in lemons and they don't put a whole lot into it lest it become too acidic. I think the main danger here is the sugar.

It should also be noted that a lot of teas contain* dangerous levels of pesticides, increasing the risk of parkinsons.

*https://www.snopes.com/fact-check/tea-and-pesticides/ (this might not be true anymore, we don't really know afaict)