Looking for explanation on the issue with Z790 boards sharing PCIe

PCIe Motherboard pcie 5 0 slot PCIe is twice the speed of PCIe , while still maintaining downward compatibility Our PCIe gen-5 protocol analyzers are capable of supporting pciex4 slot 2 slots, PCIe® NVMe® SSD slot onboard, PCIe x16 SafeSlots with PCIe Slot Q-Release, two Thunderbolt™ 4 ports, USB 20Gbps Type-C® front-panel

pcie x1 slot function This server features multiple PCIe slots to meet the demands of AI and high-performance computing workloads, including supporting up to two dual-slot