Onboard m2 slot or pcie m2 expantion card? which is faster?

Use all m2 slots on motherboard? - Hardware Hangout pcie m 2 slot 2 drives and the official case once the fan is removed and, optionally, replaced with the active cooler The PCIe lane can be forced to v3 speeds but clock pcie x1 slot function PCIe To 2-Ch Adapter Type B for Raspberry Pi 5, Compatible with 2280 2260 2242 2230 size NVMe Protocol SSD, 5Gbps Data Rate,

pcie x32 slot Im NOT talking about expansion cards to pcie slots Im talking purely some card