"I still don’t get what do you do as root to own files. Though everything is handled via emby or the windows software."
I record a Tv show. For instance "Friends". I record it for a couple years and eventually I will have every episode. Once I have them all I no longer need to record them. So I will move them to an "Archive" drive. So occasionally I manipulate the files through ssh as root. When I do (I assume) root becomes the new owner. I could move things around through SMB share but I'd prefer to have as few of them an I can get away with.
Emby is cross-platform. I doubt they will ever have any file permission setting. I think they assume access to all files. On the Debian distribution they create an emby user and emby group. I think it's up to the user to make sure that user and group have access to files and folders.
"Samba option in share “enable permission inheritance”, don’t bother with acl. After that try create a file a folder through windows and check that file is no 664 or folder 775."
Ok, done. I copied a folder over from the windows box through the SMB share. It is owned by Robert. Emby scanned the folder and created .nfo files which it owns. I have a duplicate video file (owned by Robert) so I went in through the emby app and removed it.
So Emby successfully deleted a file owned by Robert. Which is good. So I guess everything is okay. Ugly, but okay.