NCP: Errors when reinstalling/resetting

NCP 1.16.3 and Nextcloud 16.0.4, reinstalling in order to then restore from backup (changing USB drive).

Did a ‘nc-nextcloud’ and ‘nc-init’
Now I get :

Nextcloud is not installed - only a limited number of commands are available
There are no commands defined in the “config:system” namespace:

when going through configuration/network/ and other settings.

I was able to move database to USB drive, but when moving datadir I get:

There are no commands defined in the "config:system" namespace.  
 Error reading data directory. Is NextCloud running and configured?

Also, are there any special things to do for the new USB disk to be properly recognized and used (owner/permissions) ? Can’t remember if I did anything special the first time. It’s formatted ext4.