Converting Maildir to Outlook-readable EML

As the title says, I've recently been in charge of a move from a dovecot IMAP server that I have no control or access to to O365. One of the users did not manage to get their data migrated off the old IMAP server before the cutover, however I have the Maildir file from the Dovecot server. I've managed to get it to where I can see the emails in Outlook via an EML file, but instead of having multiple messages per folder I have a single email that appears to contain the text of all the emails.

Anyone got a better way of going about this that won't leave me with a mess of single email strings?