With all the fuss about the new EAC, it's good to note features that still aren't available in the online version. Like how to export mailboxes to PST files. I don't normally like doing anything with PSTs, but sometimes you must grit your teeth and use what's available. In this article, we explain how to use a content search to export the contents of a user mailbox to a PST file.
https://practical365.com/export-mailboxes-to-pst-exo/