(Posted this in a different topic, but the original poster was having a different issue so I'm moving it to a new topic).
The Mac build can't download on the itch app due to uncompression problems. Not sure how to fix it, but if you're using butler (which I assume you are since the files are above the 2gb web limit) you could honestly just push the .app without bothering to .rar compress it - the file size savings don't seem that important, plus patch shipping would mean much faster updates (partial updates can't be done with compressed files).
https://itch.io/docs/itch/integrating/compatibility-policy.html (itch's file type policy, goes over some reasons to use native apps instead of archives)
https://itch.io/docs/itch/integrating/platforms/macos.html (super short page on best macos build practices)