If you want to import PST files to Gmail, then check out the given blog post. We will describe both the manual method and a third-party tool.
The manual method involves downloading the PST file, uploading it to Outlook, and then syncing with Gmail via IMAP—a time-consuming and complex process. Alternatively, you can use the Shoviv Gmail Backup and Restore Tool, which simplifies the migration with a user-friendly interface. It supports bulk PST imports, preserves folder hierarchy, and ensures data integrity. The tool also allows selective migration and handles large files efficiently. For a hassle-free solution, Shoviv Gmail Backup and Restore is the best choice.
Read this blog for a step-by-step guide on both methods!
https://www.shoviv.com/blog/how-to-import-pst-file-into-gmail/