How to export e-mail messages from the Samsung Email app on a Samsung Galaxy S23 Ultra

A colleague of mine had his e-mail messages deleted from their e-mail account by accident. This happened quite a few weeks ago so he did not notice this until now. By now all the backups of his e-mail account already do not contain these messages anymore. But he did not check his e-mail on his mobile phone (Samsung Galaxy S23 Ultra) and so his mobile e-mail client (Samsung email app) did not sync with the IMAP server. We have disabled the sync, so he can see the older e-mails in his Samsung Galaxy S23. The question now is, how to get these e-mails from this app? There are more than 5000 emails on the phone. We would like not to have to root the phone to get this done. Does anybody know how we can get his e-mails from the phone? Even if they do not have attachments, that is no problem. We tried using ADB for the backup of com.samsung.android.email.provider, but his does not seem to work - the backup file is empty. We tried My Backup app, but this still has not finished the backup process so I do not know if this will work or not. Any help would be greatly appreciated.