Does this only apply to TikTok or any other "foreign adversary" application that collects user data?
What's stopping another version of TikTok from being created, effectively defeating the purpose of banning a single app?
It’s very difficult to recreate the network effects of an app like TikTok. If it were easy, Zuckerberg would have already done it.
It doesn't defeat the purpose. You can just make a new ban. There would be less friction since there is already an example.
You could have read either the law or the decision, linked in the comments here, to get the answer to this question.
From the decision:
> Second, the Act establishes a general designa-
> tion framework for any application that is both (1) operated
> by a “covered company” that is “controlled by a foreign ad-
> versary,” and (2) “determined by the President to present a
> significant threat to the national security of the United
> States,” following a public notice and reporting process.
> §2(g)(3)(B). In broad terms, the Act defines “covered com-
> pany” to include a company that operates an application
> that enables users to generate, share, and view content and
> has more than 1,000,000 monthly active users. §2(g)(2)(A).
> The Act excludes from that definition a company that oper-
> ates an application “whose primary purpose is to allow us-
> ers to post product reviews, business reviews, or travel in-
> formation and reviews.” §2(g)(2)(B).