Michel, while your gathering info to post so that Mr. Harvey can help you, would you also please update your profile to reflect which version of Zorin OS you are using?
Thanks!
Now in regards to PCIE NVME M.2 drives, they don't connect exactly the same as SATA drives do. M.2's use the PCIE gen 3 and gen 4 lanes on the motherboard, and they are usually configured in RAID.
I am still learning about these new drives myself, but what little I know, I understand like on my notebook for example, they have to be enabeld for RAID for both drives to be seen and used on the same motherboard.