Short answer, no. WD had decided that the public folder cannot be changed to private. If you do a forum search you’ll find several past threads on the Public Folder issue. Prior to the OS 3 firmware one could exploit a bug in the Dashboard coding by trying to change the Public Share name which would cause the Public Access option to become selectable, but that coding was “fixed” starting with the OS 3 firmware.
Two recent threads on this issue:
https://community.wd.com/t/removing-public-share-wd-mycloud/137086
https://community.wd.com/t/public-share-public-access-on/96854
