Let me see what I can do for a Mac build. I was doing some research on like additional things that might be needed but checking the deployment options in RPG Maker there is one for Mac? So I'll give that a try. I don't really have any means to test it since I don't own a Mac, but let me see if I can get one out here in a second.
I imagine the browser saving issue could be a Mac issue or a browser issue, I'm not certain. Let me look into that Mac deployment though.