Can't move directory to new drive

Hello together,
I recently installed NextcloudPi and after tried it out for a little bit I ordered a new 2TB hard drive to start daily using it. But when I tried to move my datadir I always got the following error:

[ nc-datadir ] (Sun Feb 19 17:19:41 GMT 2023)
Maintenance mode enabled
moving data directory from /media/NextcloudData/data to /media/USB-Drive/NextcloudData...
{"reqId":"hs2HO1Dr93e4ktC1oQCP","level":2,"time":"2023-02-19T17:19:44+00:00","remoteAddr":"","user":"--","app":"no app in context","method":"","url":"--","message":"Temporary directory /media/NextcloudData/data/tmp is not present or writable","userAgent":"--","version":"25.0.3.2","data":[]}
Nextcloud is in maintenance mode, hence the database isn't accessible.
Cannot perform any command except 'maintenance:mode --off'

Your data directory is invalid.
Ensure there is a file called ".ocdata" in the root of the data directory.

Cannot create "data" directory.
This can usually be fixed by giving the web server write access to the root directory. See https://docs.nextcloud.com/server/25/go.php?to=admin-dir_permissions

An unhandled exception has been thrown:
Exception: Environment not properly prepared. in /var/www/nextcloud/lib/private/Console/Application.php:166
Stack trace:
#0 /var/www/nextcloud/console.php(99): OC\Console\Application->loadCommands()
#1 /var/www/nextcloud/occ(11): require_once('...')
#2 {main}
Nextcloud is in maintenance mode, hence the database isn't accessible.
Cannot perform any command except 'maintenance:mode --off'

System config value logfile set to string /media/USB-Drive/NextcloudData/data/nextcloud.log
Nextcloud is in maintenance mode, hence the database isn't accessible.
Cannot perform any command except 'maintenance:mode --off'

System config value tempdirectory set to string /media/USB-Drive/NextcloudData/data/tmp
Installing template 'php/opcache.ini.sh'...
Maintenance mode disabled
Installing template 'ncp-metrics.cfg.sh'...
The NC data directory has been moved successfully.

After I did some research, I found I had to add the .ocdate flle into the directory, so I did this. When I tried again, I got no error anymore. datadir confirms that everything should be where I want it to and my System Information tells me the same, but under data disk usage it still shows only the SD Card. Sorry if this is a stupid question, I am trying this for the first time. What should I do?
Would be very thankful for every advice.

NextcloudPi version v1.51.0
NextcloudPi image NextCloudPi_RaspberryPi_v1.51.0.img
OS Debian GNU/Linux 11. 5.15.61-v8+ (aarch64)
automount yes
USB devices sda
datadir /media/NextcloudData/data
data in SD yes
data filesystem ext2/ext3
data disk usage 3.1G/29G
rootfs usage 3.1G/29G
swapfile /var/swap
dbdir /var/lib/mysql
Nextcloud check ok
Nextcloud version 25.0.3.2
HTTPD service up
PHP service up
MariaDB service up
Redis service up
HPB service up
Postfix service up
Internet check ok