Thanks for your post. I have 3 additional comments:
- Neither of the two Ciphers you have configured are using the MACs.
- sntrup761x25519-sha512@openssh.com
has been in OpenSSH since around 8.5. It's not required to use OpenSSH 9.9 on the client to benefit from post quantum key exchange. - Just for the record: "Host Key algorithms ssh-ed25519" is not PQC safe, but PQC KEX offers some protection against store and decrypt later.