So…in order to achieve a result like that, Trump would have to show that it was likely that he would have won his case but for that error. That’s a high bar. There’s no guarantee he wins with a jury trial, it’s just usually a good idea because juries are easier to legally influence than a judge. But that can go both ways in civil cases, honestly, so it’s not a guarantee that you win. So a do-over has almost zero chance of happening on a claim of legal malpractice. Maybe he could get a partial judgment against his own attorneys, but even that’s unlikely.
ETA: Juries are notoriously unpredictable. While I agree this was a mistake, I don’t think it’s the massive error it’s being made out to be here. Although it is interesting that Trump has been attacking the judge when his own lawyers could have minimized the judge’s influence by simply requesting a jury trial.