Did you contact Valve or have the person who bought it contact Valve to report it as stolen?

I use this. They’re very effective.

Theyre called MoCA adapters

This whole website reads like trash.

Do you host anything on your network to tne internet that allows anyone ssh access to your computers? More simply do you have port 22 open on your router or firewall? If you don’t or said no, then don’t worry about it.

I always liked Mikrotik. Not the most open of router but the most documented and configurable I’ve seen with a web, gui, ssh, or telnet I’ve seen