State courts don't have the authority to grant the relief being petitioned for in the first place. A lot of the demands being shut down are simply that, not any ruling on the merits, up *or* down. Likewise, a lot of the things being lauded as wins for Trump are really only routine preliminary rulings. None of these cases have gotten into the meat of things yet, and that's not actually due to corruption or bias as far as I see; it's simply that court proceedings are a slow mechanism. Emergency orders are the only thing that happen quickly (emergency orders literally exist *because* the courts are slow), and that's also why they err on the side of freezing things and preserving evidence.
Likewise, Governor Kemp refusing to intervene as directly as Trump wants him to. He simply does not have the authority to do so.