If you are that paranoid, you also shouldn't use any computer at all.
Tech and surveillance are advancing too much in too many ways not to be paranoid. I'd rather be overly-cautious than let anyone supervise me. I don't like being watched, so I'd rather take my time and eliminate all potential risks and sources of information leaks. Even if they don't watch me, I personally find these practices as a very interesting and fun hobby to have. And
why not, as long as you aren't hurting anyone.
Using the main power line is another way to exfiltrate data from air-gapped systems. And this actually does work. Powerhammer is doing exactly this.
Doesn't that require having malicious hardware and software though? I mean, no matter what you do electronically, there still is
some level of trust you require because you obviously can't begin creating your own efficient hardware components. For that, I'm still waiting for the possibility of owning fully auditable Open-Source hardware.