Hi Raymond, 

 You might need to add your ed25519 public key to here: SSH Keys · User Settings · GitLab

 Make sure the same one which is in your .ssh/authorized_keys and which you know is the one letting you ssh in, is also added to that list in the gitlab UI.  I think your "rtoy" gitlab user and your "rtoy" shell login account are treated as two different things so the requisite public key has to be in both places.