Could not load host key: /etc/ssh/ssh_host_ed25519_key in /var/log/auth.log
Solution 1:
You can generate the missing hostkey via:
ssh-keygen -A
ed25519 is a bit faster and more secure. It's not necessary and, aside from logspam, this doesn't have that much effect. You could, indeed, comment out HostKey /etc/ssh/ssh_host_ed25519_key, without much effect. But, at the same time, `ed25519 is a good host-key format to support.