Oh gosh, still no success. My first mistake was trying to play games on a Mac lol! Is there anything I can do on my end, or info I could dig up, to make this easier to diagnose? I worry I might have left something out.
Maybe you can try starting the game through the itch.io app, it seems like a lot of games that have been "unsigned" like mine have the same issue, caused by the macOS Gatekeeper.