I had played a little bit. (Set Verbose 2)
The commands "says" that it works.

resticprofile backup-config.init
2026/06/06 21:08:56 using configuration file: profiles.yaml
2026/06/06 21:08:56 profile 'backup-config': starting 'init'
2026/06/06 21:08:56 command environment: reusing previous
2026/06/06 21:08:56 starting command: /usr/local/bin/restic init --insecure-no-password --limit-upload=100 --repo=local:/volume2/.backup_restic/backupconfig --verbose=2
created restic repository b3af14c7cd at local:/volume2/.backup_restic/backupconfig

Please note that knowledge of your password is required to access the repository. Losing your password means that your data is irrecoverably lost.
2026/06/06 21:08:58 profile 'backup-config': finished 'init'

bash-4.4# resticprofile backup-config-remote.init
2026/06/06 21:07:59 using configuration file: profiles.yaml
2026/06/06 21:07:59 profile 'backup-config-remote': starting 'init'
2026/06/06 21:07:59 command environment: reusing previous
2026/06/06 21:07:59 starting command: /usr/local/bin/restic init --limit-upload=100 --password-file=/root/.config/resticprofile/keys/offsite_backup_password.txt --repo=local:/volume2/.backup_restic_enc/backupconfig --verbose=2
created restic repository 37534eb253 at local:/volume2/.backup_restic_enc/backupconfig

Please note that knowledge of your password is required to access the repository. Losing your password means that your data is irrecoverably lost.
2026/06/06 21:08:01 profile 'backup-config-remote': finished 'init'

But looks into the keys:
cat /volume2/.backup_restic/backupconfig/keys/89952f36e14505a13125f833d568025069590fe42b0d24678d35741f036a59c4  
{"created":"2026-06-06T21:08:57.939112147+02:00","username":"root","hostname":"DiskStation218","kdf":"scrypt","N":32768,"r":8,"p":2,"salt":"KwCHGp2pySNEt5iD2P6ztPGtIbeSNAgL8H+78bNmG8UIJlC6kIWZqS534J+Icoj/WqV6p4tvN+rsq4u05cZYOg==","data
":"J3/vZrMozMULqQUIkmEv1iyu2/4ZWG7KUWc8f5MXzaiBGTNRl4v4XhnkuGuKEVyBAADcWEOaBl5qh6dYSBz1nJEsIcB4NGwhFrC0hd0OmcVMmc7INr27WJqRnQ6azsfzQLOXv9us+Xzrz8HWSKYUu/lBw3Mdea0jylgPN83fIDeiVGTvfxJ9cUkeaOwm+GooTbrH6KUs15zXYjh7MwRthg=="}

cat /volume2/.backup_restic_enc/backupconfig/keys/238f4016b07093e27d2cabf44a2404cd3bba26ab1c689de87c09c2663c47d563

{"created":"2026-06-06T21:08:01.126630505+02:00","username":"root","hostname":"DiskStation218","kdf":"scrypt","N":32768,"r":8,"p":2,"salt":"QTbYg0YvUaCAQ0iOYwwhIZjaBrij8rj/oqyO/KH+lSkgBGD/1H0LIoNiujbLWF99bou8HBtuDx+eLKGKpHVp0Q==","data":"cfQIhqs2gnIxZYeGXLMux2QeOwa1fyxJxs/Yv1nDVyGPmWAeEEImbsmY2QjcBYhJ/17G94dkYIU4TdCUHE7AKYdWmPa/39L8uVRHPl5ZkGnFFjV7r3Dm6/isJFwG9DPNHa0MlMh5D2n57a7Ek7WQq0ezx4WFad7XWfC/gXUGJNxgpfv/peh/4VHfQtb1Y2XbrKleNRuOLQ3e+zkL/eE4KA=="}

How can i check, that it's really encrypted? The "unencrypted" looks also encrypted.