Hello,
Which version and license of phpdocx are you using?
About your question, if we understand it fine, you can clone a block using this method:
https://www.phpdocx.com/api-documentation/docx-path/clone-blocks-in-docx
Or clone a single content using this method:
https://www.phpdocx.com/api-documentation/docx-path/clone-elements-in-docx
After you have cloned the block, you can replace the first placeholder using the firstMatch option available in the template methods, then use this same option to replace the next match and so on. Or use DOCXPath with a customQuery.
Regards.