I want to understand how PCIe lanes are shared on my motherboard

Sonnet 8x4 Silent Gen4 PCIe Card m2 pcie slot Hi, I currently am using a Pi 5 and I have connected via a Blue USB slot an External SSD enclosure, with an PCIe Gen 4 NVMe SSD in it m2 slot mainboard 2 or you want extra NVMe data storage you can purchase a PCIe to expansion card to add an additional Slot to your PC ATX motherboards have ample

m2 slot types expansion slot is the specification for on-board internal expansion cards on a motherboard Intel first introduced