What about propaganda outlets like Newsmax and OANN? Many would argue they've had far more harmful impact on the USA than Tiktok ever could. Where do you draw the line? It has to be domestic propaganda? Can you prove that those don't have foreign links?
You draw the line SOMEWHERE, just like you always do, for every right already. We already have lines all over rights, and it's not crazy to add another line somewhere and let the judiciary move it around and change it's shape. That's their job.