I don’t think the national security concerns have been well asserted. What’s the specific national security issue, and the evidence of TikTok doing it?
The app is owned and controlled by the Chinese Communist Party. Basically the equivalent of a Chinese citizen using a CIA-controlled app to get their news. It's a very bald-faced security threat.
Furthermore, China has explicitly banned any American social media from the Chinese market for years. They know it's dangerous letting foreign nationals control your narrative, probably because they've been exploiting social media for years.
Oh, and there's also the electoral controversy: https://kyivinsider.com/russia-and-china-just-rigged-romania...
It’s not. It’s 60-something percent owned by international foreign investors outside of China. TikTok user data in the USA is held under TikTok USDS and managed mostly by Oracle as far as I know.
We are in a standoff situation where the only smart move is to call China's bluff. It will hurt Apple, it will hurt TikTok users, but it will match China's policy of fighting market infiltration by foreign adversaries. A more functional administration would have this rubberstamped and banned in a week's time, regardless of free speech or 90% of Americans losing their FYP. Just look at how fast the EU and UK acted against Huawei. There is no such thing as a free lunch, in router technology or social media.