I don't think that's true, but a lawyer will have to answer definitively.
It would be a brand new trial, with brand new pre-trial motions. There is no way that Bragg could get a new jury seated before the election.
Nothing carries forward to a retrial except perhaps the judge, unless the defense argues that the judge's behavior showed excessive bias and asks for the judge to recuse or be removed.
-PJ
I got that info listening to Judge Jeannine Pirro. You can probably find it googling.