I know there is RaspberryPI for bare-metal ARM, but wondering if there is an x86-64 machine in which either (a) it has no operating system preinstalled installed, or (b) you can uninstall the operating system and start from scratch with assembly / boot loaders and such to install your own custom operating system (non-linux, from scratch, bare-metal, etc.). I have seen minnowboard, but it seems out of stock and with a lack of support unlike the RaspberryPI, so doesn't seem like a great option atm.
If there is a way to get an x86-64 bare-metal device, wondering where to look to get started. I have seen a few posts saying warning and whatnot, using ChromeBook to delete the operating system. But I don't know enough to determine if that is the correct way you are supposed to get to a bare-metal x86-64 machine. Am interested to know if that is the correct approach, and the warnings are basically just that you won't be able to get your Chrome OS back (which makes sense). The warning makes it seem like you won't at all be able to use the hardware anymore. I wouldn't want to uninstall the OS and then try one time to install a custom OS only to make a mistake and now the hardware is ruined. Please let me know if that is the situation, or if it is more relaxed, and after you uninstall an OS you can try over and over again to debug/install a custom OS without ruining the hardware.