Hi there, try moving it to your desktop. Macs often have conflicting permissions issues with RPG maker projects, let me know if the issue persists and I'll look into it.
Yes, in recent versions of MacOS support for 32x was ceased. There's a solution tho.
It requires messing with terminal. If you run the command (without the " and replacing [File_Route] with the actual file route (use no spaces, rename folders if necessary)) "sudo chmod -R 755 [File_Route]" You will be able to open the file.
I'm gonna record me doing this, I'd be grateful if you put this information for other Mac users