Question How good is Samsung 860 Evo M.2?

It looks like your "technician" is a bit clueless.

https://www.supero.com/en/product-series/34-c7h270-cg-ml.html#product-features-tab-content
"1x PCIe 3.0 x4 M.2 (2242/2260/2280)(M-key) "



For a SATA III drive, the M.2 860 EVO is at the top of the stack.
But....that SATA III drive does not seem to work on your motherboard.

So will M.2 ones like Samsung 970 evo pro or Kingston A2000 work on the motherboard? Also what SATA drives can work on the motherboard? Also how can I tell if it works on the motherboard or not?