See also:
https://www.openssh.org/pq.html
https://www.redhat.com/en/blog/post-quantum-cryptography-red-hat-enterprise-linux-10

To enable KexAlgorithms option "mlkem768x25519-sha256" for OpenSSH Post-Quantum Cryptography on Rocky Linux 10.2 (as of 2026-0905)
----------------------------------------------------------------------------------------------------------------------------------
# Change to root
sudo su -

# Create new file to enable "mlkem768x25519-sha256"
echo "KexAlgorithms +mlkem768x25519-sha256" > /etc/ssh/sshd_config.d/10-pqc.conf

# Restart sshd service:
systemctl restart sshd

# Verify "mlkem768x25519-sha256" is now enabled:
sshd -T |grep ^kexalgorithms | grep -i mlkem768x25519-sha256
# Example output:
sshd -T |grep ^kexalgorithms | grep -i mlkem768x25519-sha256
kexalgorithms sntrup761x25519-sha512,sntrup761x25519-sha512@openssh.com,mlkem768x25519-sha256,mlkem768nistp256-sha256,mlkem1024nistp384-sha384,curve25519-sha256,curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group14-sha256