What is PCIe? Understanding PCIe Slots, Cards and Lanes

Ultimate Scalibility: 4*PCIe x16 slots for Multi-GPU and 4*PCIe x4 slots; Next-gen Connectivity: Dual USB4® Type-C ports; Blazing Fast Networks

Then you also have PCIe GEN 3 and GEN 4, which are currently unnecessary until PCIe resize bar support will be more common and not dedicated only for Ryzen

pcie m2 slot Apparently the cross-compatibility and quality are quite variable PCIe = gen3 seems easier than gen4, though, and for your needs it sounds

pcie 4 slot slots for connecting additional high-speed interface Generally, a motherboard with PCIe gen 3 ranges from $ to $ PCIe gen 4