@ben Don’t worry, you’re not a pain at all!
In these cases it’s better to remove Pencil2D and any other instance of the program completely before trying anything further.
If you need to save some of your work, re-download the stable version form the website after removing the software and export your animation using PNG image sequences so you can later import them into other programs.
Along that, once you’re done doing backup for your files, then remove Pencil2D and try the development build.
If you still can’t export an mp4 movie with that, please try to export an animation GIF, if that doesn’t work yet, it may mean that macOS is blocking Pencil2D exporter plugin as well, however i’m way out of my league in regards to macOS systems, so if the security permissions are not lifted from “ruling” over Pencil2D despite you having “unlocked” it on the appropriate dialog, I’m not sure what other alternatives we have to improve on this problem .
Honestly, and this is just me ranting, both Apple and Microsoft really messed everyone up with their permissions crazyness, other free applications have had similar issues (though they have more stable funding so most of them have been fixed recently)
Unfortunately until we can find a way to fix this properly I kindly suggest trying out a different animation software from the list I shared before