Do you have any other storage drives on your build, outside of the SSD's listed above? FYI, there's no such thing as a Samsung 980 Evo, there is however a 980 Pro and a 980(non-pro) variant. For your platform, if you've got nothing populating slots M2_1 and M2_2, I'd pick the Samsung 980 drive and populate slot M2_2. M2_1 supports a maximum speed of PCIe 2.0x4...which means you'll loose out on any investments you make towards an M.2 drive for the aforementioned slot.
You forgot to mention what the drive will be used for.