1. You're not going to use it. T480 already struggles with web browsing, and if you go older then it's gonna be even worse.
2. If you were actually schizo you'd be compiling libreboot by yourself and verifying it has no binary blobs to make abundantly sure it's safe. IIRC Libreboot for the newer machines like the T480 utilizes binary blobs, so you're still using a mystery black box that might as well be a backdoor. Same with all the software running on it. Have you verified and manually compiled every line of code of your Linux distro, or are you just blindly trusting that it doesn't spy on you?
3. Once you realize that the moment you step out of your house you're already in the near vicinity of countless smartphones, CCTV cameras and satellite imagery then your only escape from being spied on is killing yourself.
Oh yeah, and even if you go through all of that you're still going to be relentlessly spied on while browsing the web. Libreboot is a meme. So is being overly schizo about backdoors and spyware to the point of being compelled to use Libreboot. It sure sounds liberating to force yourself to use antiquated hardware for some faint sense of privacy that's hardly even there.