It looks like when an attachment is deleted (Attachment.IsDeleted = true
(services/data/v52.0/queryAll/?q=select+IsDeleted+,+body+from+Attachment+where+id='00Pe0000008ELB4EAO') ), the record goes to the Recycle Bin and the body gets hidden.
One of the option would be to restore the attachment, get the body, and delete the attachment again? Although it's not ...
I was able to read a csv file from attachment record, using below apex code:
Attachment attachmentRecord = [Select Id,Body,ContentType from Attachment WHERE ParentId = <Parent Record Id>];
csvAsString = attachmentRecord.Body.toString();
csvFileLines = csvAsString.split('\n');
You can get the contentdocumentlinks from Order:
List<Order> orders = [SELECT Id, (SELECT Id, ContentDocumentId, ContentDocument.Title, ContentDocument.ContentModifiedDate, ContentDocument.LatestPublishedVersionId, ContentDocument.LatestPublishedVersion.VersionData, ContentDocument.LatestPublishedVersion.FileType FROM ContentDocumentLinks WHERE ...
As it was already mentioned, Jitterbit doesn't allow you to automate this process. Check out this step-by-step tutorial. Following it, you can easily mass import data into Salesforce on schedule https://skyvia.com/tutorials/how-to-import-data-to-salesforce