Files in the Sdui cloud are not enabled for editing by default.
The following rules apply to editing:

Normal cloud folder, editing not shared:
If the file has not been approved for editing, it can only be edited by the group admin and the creator of the file. All other members of the group cannot edit the file.

Normal cloud folder, editing enabled:
If the file has been approved for editing by the admin of the group, it can be edited by any member of the corresponding group.

Delivery folder:
Since only the group admin and the creator of the file have access to files in the delivery folder, they can be edited by both at any time.