A lot of suggestion about SMB support after the recent upgrade of OSMC it’s can be also fouded on this thread:
https://discourse.osmc.tv/t/smb-shares-cannot-browse-after-update
Some user has tryed to mount the hdd using ftab files and automount the hdd at start of osmc using the protocol cifs… i thinks you can try to ask to know secure info and secure suggestion about this 