Hey i have a HP Z8, with c622 chipset, 2xGOLD XEON, managed to boot, install MOJAVE, i have 2 main problems USB 3.0 and my nvme ssd is seen as external, due to this cannot update system. Thxmaybe I can help you make it work.
It seems that another guy built a Hackintosh as well. Man I already have the hardware and I can not find a guide to build mine. https://browser.geekbench.com/v4/cpu/14618647
It's not another guy... It's the same guy (DSM2) it's one of his Screenshots he posted while he tuned his Overclock on air.
Yes, I run it since a couple of weeks now.