Which Slot to use?

is a new form of connectivity that allows a SSD to connect directly to the PCI-E bus rather than going through a SATA controller By

I want to add SSD drive in my notebook I find M2 slot marked as M2X3 What type M2 SSD can I use?

sata 3 slot AFIK the slots are SATA only, no NVMe it say nvme on sinology web site Comment

sata slot I'm not exactly sure howif this will work though I specifically want to be able to access NVME SSD, but would settle for SATA SSD