If you want to continue using NW.js, stick to the r449.x LTS releases. However even those will eventually be unsupported, so my advice is to switch to the Windows, macOS and Linux export options instead.
I don't think export with windows webview2 will work for me because in the exported folder json files are directly available for the user to edit and the kind of game I'm building is not meant for this to be easily accessible.
Enable the 'Bundle assets' option for the Windows WebView2 export and it will hide your files much like the NW.js 'Package assets' option did.