Rule to move specific emails from Inbox subfolders to Inbox main?

You dont really need a rule for this. Simply do a search for all messages received prior do the specified date, including the (sub)folders in question in the scope. Then, simply drag and drop them to the Inbox. If you want to do this in batches, you can of course do the search in each folder or simply add the Folder field in the search results, which will allow you to sort/group the results by subfolder.