The claim that it's a "national security" risk and the ban is needed to mitigate that is silly. If it is really that then ban it from government facilities and devices. The actual risk from TikTok is no greater than the risk from Facebook, Instagram or any of a myriad of apps.
The correct thing to do would be to strengthen laws that address the core concerns so that we are protected from ANY app that represents a threat to privacy or security. Just banning a single app (and then another, and another...) is ridiculous and goes against a number of things this country is supposed to stand for.