That's due to the communication protocol. 2.5 inch and M.2 SATA SSDs max out around 550MB/s due to the limits of SATA3 connections which cap out at 6gbps. M.2

That's due to the communication protocol. 2.5 inch and M.2 SATA SSDs max out around 550MB/s due to the limits of SATA3 connections which cap out at 6gbps. M.2 NVME SSDs meanwhile communicate over PCIE, generally using four lanes, and the latest PCIE5 SSDs can do around 15GB/s if I recall. PCIE4 drives can get up to around 7GB/s, and PCIE3 drives up to around 3GB/s. Other potential bottlenecks can occur with the motherboard chipset, controller, and NAND flash, but details. TL;DR: Any NVME SSD can saturate a 10gbps ethernet connection.