When I try to open the app on MacOS it doesn't let me, it gives me some kind of error that prevents me from opening the game

the itch app can't uncompress the rar, so the mac version can't be downloaded from the app. seems like its down to file permissions. given that you're using butler (i assume, given that the rars are over itch web's 2gb upload limit) it might actually be best to just push the .app without compressing.

https://itch.io/docs/itch/integrating/compatibility-policy.html

https://itch.io/docs/itch/integrating/platforms/macos.html

https://androgyny.miraheze.org/wiki/Tales_of_Androgyny/F.A.Q.

Try seeing the third link on this page