(I'm not even American, and I don't care much about all this US TikTok nonsense. The entire shitstorm is deeply amusing to me as a side observer, as Americans seemingly learned nothing from the experience of my country)
The point of my response is: sometimes you have to be paternalistic, and the federal government doesn't need to meaningfully defend the ban to someone who doesn't like it because those people don't matter. They meaningfully defended the ban to the courts.
My point is that I don't think "access to this information services will stoke negative sentiment towards the US government" is a good reason to ban access to said service in a liberal democracy. It would be a good reason to ban the service in an autocracy of some sort, but standards for individual freedoms are higher (though not infinitely high) here. At least, they ought to be higher. That's where the disagreement comes from: I do not care that access to TikTok threatens the US Government. I care about US citizens generally. The interests of these two parties are increasingly disconnected, a sign of a decaying democracy.
This paternalistic framing is the disconnect between you and those opposed to the ban. The idea that it's TikTok insidiously worming its way onto American phones like a virus. In reality, people download the app and use it because they like it. This ban will, in effect, prevent people from accessing an information service they prefer. You must acknowledge this and argue why that is a worthy loss of autonomy if you want to meaningfully defend the ban to someone who doesn't like it.
If it helps, reframe the ban as one on a website rather than an app. They're interchangeable in this context, but I've observed "app" to be somewhat thought-terminating to some people.
For the record - I would totally support a ban on social media services that collect over some minimal threshold of user data for any purposes. This would alleviate fears of spying and targeted manipulation by foreign powers through their own platforms (TikTok) and campaigns staged on domestic social media. But just banning a platform because it's Chinese-owned? That's emblematic of a team-sports motivation. "Americans can only be exposed to our propaganda, not theirs!" How about robust protections against all propaganda? That's a requirement for a functional democracy.