You are wrong, and linked articles from US intel community have been available for years.
Maybe you mean something like this “study” https://www.msn.com/en-us/news/world/tiktok-data-suggests-al... which concludes with “kinda maybe looks like they could possibly favor Chinese interest”. Doing a study and putting out a headline is all it takes to poison the public opinion and exactly what I would expect from the social media companies foaming at the mouth losing market share.
The wording I have seen is congress had a internal meeting about the potential security concerns that could be involved (very likely with every app).
Very easy example to find: https://www.military.com/daily-news/2019/12/30/army-follows-...
One of many, hence not linking.
Every TikTok fan is demanding proof that was provided several years ago and they ignored.