The Script I used was
I only modified the Script for my setting (data folder e.g.)
…so there IS a Script for changing the Nextcoud Folder Permissions (still valid for the NC 12.x Versions …)
https://docs.nextcloud.com/server/9.0/admin_manual/installation/installation_wizard.html#setting-strong-directory-permissions
“The easy way to set the correct permissions is to copy and run this script. Replace the ncpath variable with the path to your Nextcloud directory, and replace the htuser and htgroup variables with your HTTP user and group:…”