CP074-1_4 x NVMe SSD to PCIe x16 Mobile Rack

this mobo has three pci-e slots physically 1x16lanes ,2x1line What i found, the x16 slot is supporting only one pcie line according to

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

nvme vs m2 slot Utilize an available PCIe x4 expansion slot for the installation, removal, or interchange of PCIe SSDs The drive tray accommodates M-Key NVMe SSDs

nvme slot vs m2 2 x16 PCIe x16 card, which is used for high-performance PCIe NVMe SSDs, are inserted into PCIe slots, which may or may not be installed