You could also consider using this method: dump the archive to PST and then import the PST into the mailbox
Following example steps will help to copy data from Archive mailbox back to mailbox.
1.Assign permissions to the account to do data exporting:
New-ManagementRoleAssignment -Role "Mailbox Import Export" –User "your name"
2.Create a shared folder with write access permission to the account and run the following cmdlet:
New-MailboxExportRequest –Mailbox "user" -IsArchive -FilePath \archive.pst
3.Check the status of the operation to understand whether it is completed or not:
4.To import the data back to the mailbox:
New-MailboxImportRequest -Mailbox "user" -FilePath \archive.pst
-TargetRootFolder "Recovered emails" switch can recover to the specific folder
A related thread discussed the similar issue for your reference here: Move Archived items to mailbox
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