Sigh, no definition of what a "desktop" would be. That would be a start. Does it have to have "on board audio" ? All my early desktops up through the Pentium 3 used an add in card (typically a Soundblaster) to provide audio. So why make it the "requirement" for a desktop? Graphics? All graphics were "plug in" in early desktops until transistors got so cheap you could throw one into the southbridge for "free." The list goes on.

It would a much better exercise to create a systems design document for what an AArch64 desktop should have, required, extras, and nice to have. Start there and work forward, not at a full fledged PC desktop with 30 years of evolution behind it and start there.