Using a third-party MBOX converter tool is always the best practice for converting MBOX mailboxes into Outlook PST format. Third-party tools are better than a manual method because there is no requirement of technical expertise besides, you easily
export MBOX files to PST format for 20 email clients such as Thunderbird, Eudora, Apple Mail, Gmail, Spicebird, and many others. Additionally, If you go for a higher license version then, this tool allows you to export MBOX files into Office 365 and Live Exchange server efficiently. This tool also offers a free trial version If you plan to buy any MBOX converter tool then, I recommend try the Shoviv MBOX converter trial first.
Read more: Extract MBOX Attachment to PST