Should I install NVMe ssd in socket or in PCIe slot using

Only if its a boot device or your intent is software raid, any most pcie adapter regardless of bios support will support an nvme data drive once

PCIe x4 interface Up to 3,3002,900 MBs NVMe compliant with APSTASPM power management support

nvme slot vs m2 No; It does not You only have a single PCIe x2 slot So only one of your devices would run at that speed However, most if not all

nvme in pcie slot By specification, all PCIe cards are backwards compatible with the lowest bandwidth x1 lane slots If the x1 slot is designed with an open end,