The law gives the President unambiguous authority to grant an extension to the timeline.
He has to certify 3 things to invoke that extension which he is unable to certify.
True, but that's a low hurdle for the new guy. More generally, its worth pointing out that the law as passed explicitly names TikTok/ByteDance, but locates a lot of authority with the president to determine 'adversary' and 'controlled' in potential future applications of the law.