Owner of the share / can not write

I have integrated several hard disks in openmediavault (Debian) and created a software RAID5 using the GUI. Since I wanted to use several partitions on the RAID, I created them through SSH using LVM (VG/LV). In the GUI I could then create the filesystem (ext4) on the LV. So far everything worked fine.

Now I have created several SMB shares on the partitions and specified the whole partition ("/") as path. Using macOS I can connect to the server via SMB. Although I as a user and my group has access to the share, I can only read, but not write.

The file system under "/srv/share-folder" is owned by "root" and the group "users":

drw-rws---+ 4 myuser users 4096 Feb 22 20:35 dev-disk-by-label-DATA

Writing is only possible if I enter myself as owner of the filesystem (chown).

What should the permissions look like correctly so that the permissions work correctly in openmediavault?

Something is completely wrong and I do not understand the relationship.

Can anyone help?

Edit: I can use the CLI as root to create files in the share and then see and read them via SMB.

I have noticed that the shares work in additionally created subfolders. As an example the folder "TEST/" works, but not the root share MEDIA "/" (see screenshot).

Since I want to share whole partitions, I am facing the same problem as some other users in the forum.