This article from 2024 gives a pretty good rundown as to why using this reasoning to ban Tiktok will set a very bad precedent:
If the govt cared about your data privacy, they would create data collection regulations that they could then use to ban tiktok if/when they violate them.
Disclaimer: I am not saying Tiktok is a great app with zero issues. This is a concern about causing long term problems by using a short term easy solution.
China is planning for long term survival, USA is planning for short term profits. Yes, China has problems.
https://www.gao.gov/products/gao-24-106866