No matter what happens with Twitter, Tik Tok will not replace it.
If Twitter does decline in importance, it will not happen suddenly. One or more of of the other platforms might expand upon what they do, or something else will come along. But Tik Tok, given its obvious link with the Chinese Government, will not / cannot be the replacement. Do you think Western governments and media will use Tik Tok like they do Twitter? Many influential people people will surely think similarly and not go there. And without all them, it cannot do anything like a similar job.