Would the Preview App help you?
Previewer Application
You can purchase this module on the marketplace: https://extensions.siberiancms.com/downloads/your-own-previewer-app/
With the update 4.14.6 we are also releasing a brand new Previewer Application module. This new previewer is completely different from the existing one as it’s not anymore a standalone application, but a “Siberian Feature”.
This means you will have to create a regular application from your editor, like any other apps, to hold your Previewer feature. For instance, you can create an app to promote your company and add the “previewer” feature to it. To preview his app(s) your client will have to download this application, and access to his app(s) by clicking the “My Apps” tab (or whatever name you give to it) in this app.