Hello,
I’d like to check on your current setup. Are you using the NW.js / Electron.js version that I provided?
Also, when testing, I recommend not using the playtest feature from the RPG Maker MV / RPG Maker MZ editor. Instead, you should launch Game.exe directly through Steam for testing.
If possible, could you also let me know which version of Windows you are using? Currently, my plugin requires at least Windows 10 or later to run properly.