Can I access an oversized PST file without Microsoft Outlook?

Yes. You can access oversized PST file without Microsoft Outlook by using a standalone PST viewer such as MacSonik PST Viewer. It supports oversized PST files and can open them without requiring an Outlook installation or active Outlook profile.
The tool lets you preview emails, attachments, contacts, calendars, tasks, folders, headers, and other mailbox data. It also supports advanced search filters to locate specific emails in large PST archives.
For very large PST files, MacSonik can also split files larger than 45 GB into smaller PST segments during export, making large archives easier to manage.
So, if your goal is simply to open, search, and inspect an oversized PST without Outlook, a standalone PST Viewer is a practical option.