Nextcloud change config to move files

[uniquegch]

Hello Yunohost community,

I have to move change the config.php of the nextcloud in my yunohost server, because the files need to be stored on dev/sda4 instead of the default volume.

I tried following the followng youtube videos https://www.youtube.com/watch?v=VHF89bZR0bg but the user www-data is not working when trying to enable maintenance mode

*sudo -u www-data php /var/www/nextcloud/occ maintenance:mode --on
Cannot write into “config” directory!
This can usually be fixed by giving the webserver write access to the config directory
*
if I use nextcloud instead of www-data then I am getting far too many exceptions.
What account do I have to use so I can modify the path in the config.php?

Thanks

[uniquegch]

Hello it seems that my question is not publicly seen? it shows being grayed out kind off. I am new to this.

Here are further information. the root partition is ext4, while the sda4 is btrfs and should hold all the files for nextcloud users, app data, Videos and Music (both in its own shared NFS folder for everyone to use. I also have mopidy running on it.
Can anyone direct me to which user account I have to use (or find out) for putting nextcloud into maintenance mode and do the path change in the configuration?

Thank you