It seems like the way forward would be to use Templater. Then you would trigger the template in the “previous” file, gather all the necessary metadata, and the content to extract or use as base in the new file.
Then the template would create the new file with either an appropriate template or your generated content, and you can leave a link in the active (aka “previous”) file.
This way you would have full access to both files, and can choose whether to (or when) to shift focus to the new file. Or potentially just create it in the background, and keep editing the active file.