That totally sounds like something I would do for fun when I was younger and had less money. In those days, all my computers were hand built by me, often using spare parts from computers people didn’t want. I didn’t work much with laptops though. It’s a bit trickier, but with the right tools and with plenty of time watching YouTube videos, you can do almost anything nowadays, and save a bundle. Also, eBay is a good source of parts, tools and expired equipment. Chromebooks are creating huge amounts of e-waste because of expiration, so reclaiming and renewing them is something I consider very ethical.

There are mod projects documented on YouTube videos and elsewhere that describe how to do just that. If I remember right, it depends a lot on the specific chromebook and the manufacturer. If I were to buy a Chromebook, I would first find out whether or not it could be wiped and have linux loaded on it effectively. I would probably opt for a lightweight flavor of Linux so as to keep the device running smoothly.

EOL. End of life. All Chromebooks have an EOL date after which they will no longer receive updates and can no longer be considered secure. All the software on them, including Chrome which is the core application, become unviable. When you find an unbelievably cheap Chromebook on sale, it’s because it’s EOL is close.

Also sounds like you’re describing a Chromebook. Which, incidentally, schools seem to be abandoning because of the fact that they become useless on a predetermined date.