> the Linux kernel and Linux distros both leave that unified memory capability up to the GPU driver to implement

Depends on if AMD (or Intel, since Arc drivers are supposedly OSS as well) took the time to implement that. Or if a Linux based OS/distro implements a Linux equivalent to the Windows Display Driver Model (needs code outside of the kernel and specific to the developed OS/distro to do).

So far, though, it seems like people are more interested in pointing fingers and sucking up the water of small town America than actually building efficient AI/graphics tech.