How to export Mac Mail to Thunderbird while preserving folder structure

I am trying to export my mailboxes from Mac Mail to be able to import into another computer that uses Thunderbird. I can export/import one folder at a time with its email contents, but I cannot figure out how to export the mailboxes with all its nested folders and emails inside. I have been using Mac Mail for about 10-15 years for my business, so I have a LOT of nested folders. Manually importing each folder with its contents is out of the question. I've tried importing the mbox folder that is auto-generated from Mac Mail in the user/libraries folder, but that imports a bunch of weirdly nested numerical folders.

Any insight would be fantastic!! I've been Googling my brains out for the past week with no solution.