Coreboot is only available for a relatively small number of motherboards and most of them are low spec (by today’s standards). The mini is (as far as I know) the only desktop-ish corebootable system that supports a modern CPU, 64GB DDR4 and USB3. If there are others do let me know! I also have a couple of Corebooted AMD systems and a Librebooted Thinkpad but they are 10+ years old.
I’ll upload the files later today.