Good point, but a clarification re Ed25519: what matters here is the host key algorithm with highest preference, not the default/recommended algorithm for the identity key. The highest preference appears to be Ed25519 or ECDSA depending on the OpenSSH version; see HostKeyAlgorithms in ssh_config(1).
https://docs.github.com/en/authentication/connecting-to-gith...
(it would actually be best to update it to the Ed25519 public key, as it's the recommended algorithm when generating a new SSH key).