You can use WSL if you know what I am saying
chmod a+x executable(AppName/Content/MacOS/AppName for MacOS)
and use butler to upload it to itch.io directly don't move it back into Windows(it messes up permissions)
this should also work with Linux
If I had access to a Mac (or any unix machine) I'd absolutely do that!
if you're on Windows 10 you can use Window Subsystem for Linux
but anyways..
Just setting up a mac virtual machine to have 0 BS