Data directory snap permission denied vs data readable by other users

Hey everyone,

I’m running nextcloud on Ubuntu using snap.
The installation process works perfectly and everything is up and running.

When I try to change my data directory however, following

I retrieve a Permission denied error when nextcloud tries to read files / open directories.

All the Directories from /mnt/hdd/nextcloud are recursively owned by root:root.
The Permissions are made using

$ sudo chmod 0770 /mnt/hdd/nextcloud/data

when trying to change permission to something more lax I get the exception:

I also tried setting the

'check_data_directory_permissions' => false,

Flag but this just gave me a different internal server Error, which I was not able to trace back.

Any Help would be appreciated.