I don't know if you have aware of PST to EML migration process but if you want to export PST data to EML file format then you need a professional tool.
However, you can also use the manual method to move the mailbox from PST to EML file format but it cannot provides you best result.
MailsDaddy PST to EML Converter is the superior application that provides conversion from PST to EML, MSG, MBOX, etc. You can use the software on different Windows OS and migrate PST to EML at once.
Read more: https://www.mailsdaddy.com/pst-file-converter/pst-to-eml.php