Well I don't think Rednote will be the replacement of Tiktok either, but the reason is the business model of Rednote in China is different from Tiktok, they don't pay their content creators for content and user engagement, instead they encourage users opening stores on Rednote. It requires a lot of efforts to turn around their business model for foreigners very quickly, not mentioning TikTok's fast growing e-commerce business in US.

Secondly, even Chinese government gave greenlight to this, I don't think US government will do the same. After all the free market is nothing compare to so called national security.