You can use this free Vartika TGZ to PST Converter tool; this software will help you convert emails from TGZ file format to PST. The software gives users the flexibility to transfer data from any version of Outlook. This is a free tool to export all your emails from TGS to PST without data loss and also to other formats like EML, EMLX, PST, HTML, MBOX and MSG.
Know more info- https://www.vartikasoftware.com/fr/zimbra-to-outlook-migrator.html#