Doubtful.
As others have pointed out, the total Chinese holdings of US securities total a few hundred billion. Such matters can be dealt with, if necessary.
Even the total US debt isn't as bad as it looks. A large chunk of it is simply notionally owed by the US Government to itself.
And a large chunk of it is not owed to itself. Further the chunk that is owed to itself is in "trust funds" that are seriously underfunded.