thanks for the correction, i'm an ATX guy, my bad.
Remember the golden rule of statistics: A personal sample size of one is a sufficient basis upon which to draw universal conclusions.
Upload the computer to Dropbox and provide a link to it so others may download it to examine and give advice for repairs.
So that DIMM.2 is for NVME drives like the Threadripper board. High density memory is mentioned on the product page but I'm not sure if that's the same thing as the double capacity ram mentioned in the article. If "high density memory" and "double capacity memory" are the same thing, it goes in the normal ram slots.