SharePoint Template Copying

Have you considered just creating a page template and the user creates a new page and updates their own metadata (if it needs to be changed)? 

You can create a page template right in modern SharePoint. When a person goes to create a new page, they are brought to the page templates list and they can select it there. In fact, you can create a separate one for each product if you want to. Then, when they create the page you've already populated the metadata and they just need to give the page a title and add any content to it. 

Here are the steps for this:
Page templates in SharePoint - Microsoft Support