I don’t believe TikTok is any bigger threat than any of the other social media apps, which is to say that they are all a threat to our privacy and wellbeing.
Based on the experience I had before retiring I would not want any software written and supported in China on my phone or any other device. I base this on when my company opened a software lab in Beijing. They were given access to systems and databases they needed to do their job. After a few months it was noticed that they had started trying to gain access to other systems and databases they had no business need for. Audits of employee systems also showed signs of network tools they were not authorized to use. Several of us in the senior technical staff were finally able to convince executives that the first loyalty of our “employees” in Beijing was to the government not the company. While we could not prove it 100% there were enough indications that the unauthorized probing and tracing was being directed from outside the lab and was likely the Chinese government or an affiliate. In the end we closed the Chinese lab and used a company site in Taiwan to handle the development of Chinese versions of our products.
As to banning TikTok it would not bother me in the least. In fact I think we need to do a better job of walling off bad actors around the world as they do not have our best interests at heart.