Ahhhh. Thank you!
So I was almost on the right track. But only almost. 
I summarize:
runagent -m loki1 nano /home/loki1/.config/loki-config.yaml
auth_enabled: false
analytics:
reporting_enabled: false
usage_stats_url: ""
Restart loki-server:
runagent -m loki1 systemctl --user restart loki-server