My concern seems to be different than that of most expressed here. Companies collecting too much information is a problem, sure, but that's not what deeply worries me when it comes to social media generating/consuming platforms like Facebook, TikTok and YouTube. Especially those that algorithmically decide what to show users.
Foreign countries controlling what information a coming generation is exposed to is IMO much more concerning than collecting and profiling (of course also troubling, but a slightly different league). There is little oversight into what bubbles are formed, who is fed what, etc.
Want to create division in a foreign country? What better place to start than on social media and malleable kids.
This applies equally to TikTok as Facebook, for different reasons. I don't trust TikTok because of CCP, and Facebook because everything is for sale.