- I have modified the guide to use a default Manjaro instance instead of the VPS example.
Copy the public keyfile to a non root user with sudo privilege on the device.
Then connect as that user and copy the keyfile to the root location.
Security advise: Do not ever enable password login for root user.
The ONLY possible exception is if it is something on your lan - inaccessible from the internet. Even then - it is not advisable due to the possible vulnerability.
Also remember that repeatedly trying to login with password (brute force password guessing) will block the user in question and you do not want your root user locked out 