SSH is a core tool in a sysadmin's arsenal. It is mainly used to remotely control a machine.
Use stronger ssh keys.
ssh-keygen -t ed25519
Prefer SSH servers available through a Tor Onion Service for stronger encryption and authentication. Consider using Onions Services Authentication. Tor also provides NAT hole-punching so you don't need to register with a DNS service nor open up your LAN to outside access. If the server is known to the public (non-hidden) one could use single Tor hops for the server, see Non Anonymous Onion Encryption and NAT Traversal.
Any references to SSH breaks in the Snowden archives applied to some outdated ciphers.
Beware of keyboard keystroke and computer mouse based deanonymization as explained under Surfing Posting Blogging.
Can be combined with Two-factor authentication 2FA (undocumented).
Configuration SSH servers to listen on non-default ports reduces noise (automated hacking attempts) as well might increase security from lesser skilled attackers.
Whonix forum discussion:
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