I'm so sorry about the inconvenience, Apple is not very friendly to indie developers haha ;-; but this post by another dev goes into how to run itch games on Mac: https://moiraimyths.itch.io/tgp/devlog/775679/troubleshooting-for-mac-users-unab...
There's a Steam version of the demo as well if you'd prefer that: https://store.steampowered.com/app/2831190/Snow_White_Ashes_Demo/