I've heard of a modded App that was made when TikTok was banned in Russia, that said, even people who live outside the US, but at one time had a US phone number associated with their accounts aren't able to access it either.
Seems Bytedance is trying to play nice with the US government - probably in hopes of Trump making Republicans reverse the ban. Because at this point that's the only way they get to stay long-term. It's probably going to upset people to see them kiss Trump's ring, but considering that the way they make money in the US is their shop, and selling ads to US companies, and both of those go away if they're banned, they need their user base loud about the ban to motivate Trump.