If you are looking for a solution that converts your Thunderbird MBOX into PST format with all attachments, you can go with MailsDaddy Thunderbird to Outlook Converter which allows converting multiple Thunderbird files at once. Additionally, this tool also allows you to export the TB mailbox to EML, MSG, HTML, MHTML & RTF format.
The demo version of the Thunderbird email converter is available on the Official site that helps the user to move the first 20 emails from each mailbox.
For more information visit: https://www.mailsdaddy.com/thunderbird-to-outlook-converter/