Hello Kopano Team,
as decribed for old MAPI client (older Outlook versions) here https://documentation.kopano.io/kopano_archiver_manual/client_features.html
there should be a similar possibility to browse and search in main store archive or in the archives of shared stores.
Not sure if there are possibilities for smooth integration in the folder tree view because archive synchronising isn’t a good option. But maybe archive access and / or search via some Outlook ribbon or KOE dialogue box would be very helpful.
Otherwise you inconvenient have to logon with Webapp even for simple archive search.