Have you checked if all containers that need to access the same volume/bind run their main process with the same UID:GID?
You need to make sure the directory/file owner and the processes in all containers that try to access them have the same UID:GID.
For instance your dokuwiki container uses environment variables PUID and PGID to configure this. This is a built-in feature by the maintainer of this image. Some images provide this feature, most don’t. You can set the UID:GID by configuring user: UID:GID as sibling entry to image:. Though, this will not work, if the container requires to be started as root…