List secrets for namespace:

k3s kubectl get secrets --namespace ix-vaultwarden

List data of named secret:

k3s kubectl get secret/dbcreds --namespace ix-vaultwarden -o jsonpath='{.data}'

List data of named secret and decode base64:

k3s kubectl get secret/dbcreds --namespace ix-vaultwarden -o json | jq '.data[] |= @base64d'

Just get the db pw

k3s kubectl get secret/dbcreds --namespace ix-vaultwarden -o jsonpath='{.data.postgresql-password}' | base64 --decode