systemd doesn't kill your SSH session (if you'd WoL your PC there's a good chance you can continue typing unless your local terminal detects that the other end goes down).

It's more that when you configure systemd to suspend your computer when there is no physical activity, it will suspend your computer when there is no physical activity.

The author wants their computer to suspend automatically.

I think modifying your system configuration to never suspend is a much worse solution than using the tool designed to prevent suspending the computer while a specific program is running to prevent suspending the computer while that specific program is running.

It'd be easier if `sshd` would permit you to wrap the incoming command line/shells so `sshd` would spawn your session with systemd-inhibit, but I don't think that's possible?