Hello,
Yes, a PCIe is required because this mobo has only one M2 (NVMe/SATA) slot. Samsung 970 EVO+ bandwith beeing 3.0 x4, only PCI_E4 can be used if you want to use the NVMe drive at its best performances (I suppose PCI_E1 is used for graphic card). Because PCI_4 is 3.0 x4, it is useless to select an adapter for more than 1 drive; many are availables.
Have a good day,
