Excellent article on TikTok, China, and liberalism from a mostly non-technical vantage
https://stratechery.com/2020/the-tiktok-war/
That means that TikTok data absolutely can be sent to China, and, it is important to note, this would be the case even if the privacy policy were not so honest. All Chinese Internet companies are compelled by the countrys National Intelligence Law to turn over any and all data that the government demands, and that power is not limited by Chinas borders. Moreover, this requisition of data is not subject to warrants or courts, as is the case with U.S. government requests for data from Facebook or any other entity; the Chinese government absolutely could be running a learning algorithms in parallel to ByteDances on all TikTok data.
If anything it would be a something of a surprise were it not; an important piece of Chinas thousands of years of history is the presence of a bureaucracy focused on collecting data on, well, everyone and everything. I see examples of it here in Taiwan, where my household is registered, cameras are everywhere (and routinely accessed), and cellphone data is a pandemic fighting tool, and this is a democratic country based on liberal values. China, which combines this tradition with a totalitarian government, takes data collection to the max. Facial recognition is omnipresent, nearly all transactions, even in the real world, are digital, and social networks like WeChat are completely open to censors, both from Tencent and the government; the government even hacks your computers as a matter of policy. Given this reality it is completely reasonable to be concerned about TikTok data!
much more at the link