How to download all emails from OST/PST file?

Question

Email

There are several OST (Microsoft Excange) files, you need to upload all letters with the preservation of the internal directory structure into letters in EML or MSG format, the files must be titled with the subject of the letter.
I used the program "Kernel for OST to PST - Home Version", but it names all letters by serial numbers (1, 2, 3.....N.eml), it doesn't suit me. About 5000 letters

Answer 1

There are two options:
1. Write a script.
2. If option 1 for some reason is unrealizable on our own - ask those who know how to write a script for a fee.
PS
I noticed that we are talking about OST, and not connected PST to Outlook, it may be a little more complicated.

Answer 2

I found a similar tool, hope it helps you https://www.gaintools.com/ost/pst/

Answer 3

One of my friends suggested OST to PST Converter to me when I was looking for switching Offline OST to Outlook. You should also try this WholeClear OST to PST Converter .