So I thought about getting two "500GB Samsung 960 Evo M.2 2280 NVMe PCIe 3.0 x4 32Gb/s 3D-NAND TLC Toggle" ssds for my operating systems. Two magnetical harddrives for os data and another hdd for swoaping data. So all in all two m.2 PCIe drives and 4 SATA devices.
The problem I ran into is, that the board manual says something about SATA ports which will be disabled while using m.2 ssds. In particular:
As footmark for the first slot (both SATA & PCIe 3.0 x 4 mode) "The M.2_1 socket shares SATA_1 port when use M.2 SATA mode device. Adjust BIOS settings to use a SATA device."
And for the second slot (allegedly only PCIe 3.0 x 4 mode) "The M.2_2 socket shares SATA_56 port when use M.2 PCIe mode device in x4 mode. Adjust BIOS settings to use a SATA device."