Nice write-up about Linux hardware and notebooks, FOSS firmware, coreboot and a lot more by @amosbatto:

…"Only four companies (EmperorLinux, Purism, System76 and TUXEDO Computers) maintain their own custom distro and only two (EmperorLinux and Purism) do any kernel development.
…
People comparing Linux laptops from different companies often don’t consider these differences, and how they may effect the cost and the amount of time it takes to develop the product."…

https://amosbbatto.wordpress.com/2021/10/05/reflections-about-rebranded-and-unbranded-electronics/