Mac Outlook the export button is greyed out for the Archive Mailbox

I work for a small medical center running 62 MACs running Office 365. I have run into the issue several times. So I have no way to export the archive emails. One of the work around is to toggle back to the legacy version of outlook but the toggle is missing.

In fairness I am much more familiar with Macs and apple products. So any help would be appreciated.

1) So is there a way to use the Export feature on the current version on Outlook

2) is there a way to revert to the legacy when the toggle is missing.