This is offtopic but while I suspected Louis Rossman was a conservative when he moved to Florida, it was more a hunch from my side. Did he say or do something recently?

Cold solder is what happens when the solder didn’t quite reach the temperature needed to completely melt and do contact, so it looks brittle and would be potentially a faulty connection.

With that said I couldn’t spot it in the pic

I don’t use a firewall apart from router, but if you set a firewall in all of your devices, the chances of one of them getting infected and spreading it to the others via LAN would be low theoretically.