This solution allows the SSD to use PCIe gen5 speed, but does not include a full PCIe switch so PCIe gen4 x16 from the GPU cannot be repackaged into PCIe gen5 x

This solution allows the SSD to use PCIe gen5 speed, but does not include a full PCIe switch so PCIe gen4 x16 from the GPU cannot be repackaged into PCIe gen5 x8 for the trip up to the CPU. Which is why this is being introduced on a GPU that only does PCIe gen4 x8.