I'm not sure that there's much either of them can do. Congress passed the bill, Biden signed it, and Article II Section 3 of the federal charter specifies that "he shall take Care that the Laws be faithfully executed". How can any president, therefore, refuse to execute the law that prevents TikTok from being available to anyone in these United States?
Perhaps one might argue that Biden didn't execute the spirit of the laws with his efforts to find ways to admit millions of "asylum seekers" until an adjudication date could be scheduled using an app, or by extending TPS to nationals of nations which should not be receiving it, but the immigration laws allow for a fair degree of "interpretation" by the executive agencies . . . not so with the TikTok ban.
That law specifically states that the app will not be made available to anyone inside these United States and that it may not be stored on any servers serving any individual within these United States unless the company is sold to a domestic company and no longer affiliated with ByteDance.
Sure, anyone in Canada, or Mexico, China, Australia, New Zealand, or most anywhere in Europe, can continue to access the app, post content, receive income, and all the rest. A US resident could, in theory, download the app on a trip to Mexico and access the application while there to get their fix.
The only place, that I know of, where TikTok is disappearing is the good old US of A because Congress passed a law that said national security was at risk because ByteDance could require access to the data of those in the US. Faithful execution of the laws thus requires the sale of the company to a domestic entity subject to US data laws, there isn't a "gray" area subject to interpretation within the law that was passed. I hear "Mr Wonderful" has put in a cash offer of $20 billion, but I don't think ByteDance is going to to sell . . . they can still make a lot of money off the application across the rest of the globe and even $20 billion is peanuts compared to that earning potential.
