What are M.2 NVME SSD Limits and Speed

Hello Everyone,

I am trying to pick an SSD for my LattePanda Delta 3 864. I want to go up to as much as 4TB and as fast as needed. Clearly, there is a large selection of speeds and sizes so I wanted to check here first before I guess and possibly guess wrong on a SSD drive.

I have looked around considerably for maximum specs on the M.2 B and M key ports. Am I correct in assuming that the M.2 M slot is PCI 3.0 x2 (2-lane)? If so, this would mean I need to restrict my search to a SSD 2-lane or do 4-lane scale back for 2-lane interfaces?

I searched here for this info also so if I missed something in my search criteria, my apologies.

Any info and suggestions would be VERY much appreciated. Thank you!