Export Mac Mail to CSV Using Outlook as an Intermediary

If you use Outlook for Mac, you can transfer Mac Mail emails to Outlook and then export them as CSV.

Steps to Export via Outlook:
Sync Mac Mail with Outlook: Add your Mac Mail account to Outlook for Mac.
Export Emails from Outlook: Go to File > Export, select messages, and save as PST.
Convert PST to CSV: Use an online PST to CSV converter or import PST into Outlook for Windows and export as CSV.
Disadvantages:
Requires both Mac Mail and Outlook.
PST to CSV conversion tools may have limitations.
To avoid extra steps, use MigrateEmails Apple Mail Backup Tool, which directly exports Mac Mail emails to CSV.