I tried uploading just a .exe then a .zip with said .exe but both times I re-downloaded to test them it said they were 'damaged'. Next I exported the game, zipped that and exported it, but it said the same thing. Can someone explain what files and folders I need to package to upload a GMS2 game?

Thanks!

If you're on Mac OS you won't be able to run a .exe, since that's the executable format used by Windows. I'm not familiar with Mac OS, but my best guess on the format they use for executables is a custom format based on ELF.

Try running it through an emulator such as Wine. This isn't guaranteed to work, since Wine has a lot of issues running many applications, especially graphical ones, but it's worth a try. Alternatively, you can install a Windows virtual machine using software such as VirtualBox; Performance won't be great but you will be able to verify that it works, at the very least.