If you are looking for a best PST Splitter tool, One MVP recommended tool is Stellar Splitter for Outlook, this tool can split PST files into multiple smaller parts without modifying the folder structure-based criteria like date, size, year, folder, email id etc. It can split multiple PST files simultaneously. The best part of using this software is it supports all version of Outlook.

The demo version of this tool offers a preview of complete mailbox, so that you can check and verify your important mail items before you proceed to split. Try the demo version: https://www.stellarinfo.com/split-pst-file.php