Jury trials are used to determine guilt or innocence, and judges are extremely hesitant to second guess a jury decision under any circumstances. Appeals aren't for relitigating guilt, they are for ensuring that the original trial was conducted fairly and properly. Furthermore, there's a strong bias in all circumstances against reopening closed legal matters. In general, the US court system prioritizes consistency and finality above correctness.
On paper at least, the proper legal remedy for someone who was convicted, who does not argue that their trial was conducted properly, and who nevertheless maintains their innocence is a pardon or commutation from the governor.
This undeniably sucks, but the alternative is to have the court system essentially DDoSed by felons demanding frivolous retrials.