Yeah, unfortunately, there are a lot of problems with playing indie games on macs :( I don't own a mac myself, but I've compiled a list of solutions over time with contributions from mac users who have found ways to get the games to open :3 Actually, one user in the comments below recently posted what worked for them.
User benevolent-beaver said:
"Heya, I'm on a Mac too and used to have a similar problem for a lot of games I find on itch.io. You can either:
1: Download the itch.io App (https://itch.io/app) and download the game through there instead of through the site, it should open properly
OR 2: Follow these steps
- Open the folder the game's in, right click on the game and select "Open Package Contents", then click Contents, click MacOS, you should see a file called "Yandere Heaven"
- Open Terminal, write the following command:
chmod u+x
(make sure there's a space after x)
then drag the "Yandere Heaven" file and drop it onto the Terminal window, then press Enter. The file's icon should change. Then try opening the game again."
If that doesn't work for you, you can try checking out the other possible solutions here: https://melancholy-marionette.itch.io/darling-duality-winter-wish/devlog/227880/...
Hope at least one of them works for you :3