https://f95zone.to/threads/rpg-maker-mv-engine-all-versions.32358/
You need to find the rpg version looking in the rpgcore.js file inside the www folder and search the string
"Utils.RPGMAKER_VERSION =" after that you need to download the engine, unzip it rename the www folder to app.nw and drag it in the directory Game.app\Contents\Resources\app.nw\
.
I did it for Zombie's Retreat frm Sirens domain and it worked now I can play it ( I couldn't open the Mac version in the OP not even using the chmod command), do be careful that the first couple of time it can give you the loading files error, but you just need to quit the game and reopen it and it works fine.
Another options is to get the PC update version in the OP, unzip and rename the www folder in app.nw drag it onto the resources folder ( hold the alt key while doing so) and click on merge, this way you will an updated version, the path is Game.app\Contents\Resources right click on the game.app and click on show contents in the pop up menu.