Since 2021, I’ve used a Thinkpad x220 as my main computer, which runs a free Libreboot bios and Artix GNU/Linux. I bought mine used on eBay for $100, reconditioned it with free software, and added a fully-encrypted 1TB SSD. I’ve used similar Thinkpad models over the past few years, but the x220 hits a sweet spot for me. If you want something more in line with the GNU ethos, I recommend the Thinkpad t400. It can also take a free Libreboot bios, but unlike the newer x220 you can fully remove the Intel Management Engine. Despite its age, the t400 is totally capable of running a light desktop environment and doing office work.