Mail Archive Files
How do I recover deleted archive files in mail?
Question marked as
2 possibilities...
Step 1. Click the "Mail" icon on the dock to open Apple Mail.
Step 2. Click "View" from the menu bar and go to "Show Deleted Messages".
Step 3. Click the "Trash" tab in the sidebar and you will see the list of your deleted emails.
Step 4. Select and right-click the message you want to recover, then choose "Undelete" to restore your deleted email to your inbox.
Do you have a Time Machine backup to Restore to/from?
https://support.apple.com/guide/mac-help/revert-to-a-previous-macos-version-mh15216/mac
https://support.apple.com/guide/mac-help/restore-files-mh11422/mac