hello. I used the MEG x399 matherboad and AMD Threadripper 2970wx, I have the problem same to you. I had call the AMD tech-service, they told me to try install win10 on a single SSD, and followed to use the RAIDXpert2 to get the other SSDs to RAID0 in windows10, then install ubuntu, and to see if the ubuntu can recognise the RAID0. I have not to try it, so i cannot tell you what to happen.
