Yes, its possible to restore and convert orphaned OST files with complete database by using one of the best KDETools OST to PST Converter tool. It help you to repair corrupted or Orphaned OST files database and Convert OST files to MS Outlook PST file format with emails, contacts, calendar, attachments, folders etc.
Read more info:
https://www.kdetools.com/ost-to-pst-converter.html
you can download free trial version, its allow to save first 30 items from each folders
Convert OST to PST
Convert OST Office 365
Convert OST to Exchange server
Convert OST to Gmail
Convert OST to MSG
Convert OST to Google Workspace
Convert OST to Yahoo
Convert OST to Mac
Convert OST to Thunderbird