If you cannot open /view or access PST files without MS Outlook. So, I will suggest you to use any third party tool like Stellar Viewer for Outlook as one of the best free utility to read PST files without Outlook configured. Here you can find out how you can open your PST files: https://www.stellarinfo.com/email-tools/pst-viewer.php
PST File Viewer is a freeware software for viewing and reading PST files without having to use Microsoft Outlook. This PST Viewer application effortlessly examines PST files of any size. It allows users to examine PST file metadata such as file type, file version, compression method, and so on. This application includes a user-friendly, interactive graphical interface that makes it simple to use.