Hi @Masoud Sedighi ,
As you activated major and minor versioning in your library, I think it may be a library whose content changes frequently and flexibly in your environment. My concern to your requirement is that if the documents in your document set are changed or new documents are created in the document set, Does the status also need to be dynamically changed from "approved" to "Pending"? Per my knowledge, it is hard to be achieved by SharePoint Designer.
I hope this information has been useful, please let me know if you still need assistance.
If an Answer is helpful, please click "Accept Answer" and upvote it.
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.