Appeals are for finding legal technicalities or edge cases. They do not overturn findings of fact from a jury.
That is, it used to be that way in the US, when the courts were ruled by law. In the modern US, the Supreme Court is a partisan political body, so perhaps people are confident it will get overturned because Musk is now political enough for the Supreme Court to give Musk personal favors for all his massive political contributions.
That sort of rank corruption is the only reason to be confident that Musk could ever win this silly case.