Yes, you can remove duplicate emails, contacts, and calendar from PST without Outlook, then I can suggest the best option for becouse I'm also using it. Try the TrustVare Outlook Duplicate Remover, which can quickly finds duplicate in the PST files and remove them without the help of any other application like MS Outlook. It will handle a large number of duplicate PST files without losing original files. It will support all Windows OS versions like 11, 10, 8.1, 8, and 7. The software provides a preview option before deleting duplicate PST files. You can try the free demo version before buying this tool.

Visit here: https://www.trustvare.com/duplicate-remover/pst/