Ahoy!
Currently, I don't have a Mac that would allow me to build a MacOS version. I have implemented code that is specific to Mac, but it needs additional changes so it can work fully in MacOS.
As for the save issue, I know a plugin that works with more platforms (sans web and mobile), but I cannot find the site that has it. I have the a backup of the plugin here: https://pastebin.com/ZGTmPAt9
EDIT: Uh... I noticed that this is for MV, not MZ. Not sure if there's a version for MZ, but there might be one, somewhere.