The split would likely be Douyin (TikTok China) vs. TikTok for the rest of the world. The business is already structured that way- ByteDance operates Douyin directly but TikTok operates through a subsidiary.
The subsidiary is for legal purposes only, all of the tech is built and operated from China and is subject to Chinese laws.
In fact, even after divestiture this will be the case for some time. The Chinese entity holds the IP to the algorithms and other underlying technology that make Tik Tok as viral as it is.