It also has a PCIe x4 Gen 3 slot that you could drop a SATA card in if you really want to go big. A 10 second search turns up plenty of options that will turn

It also has a PCIe x4 Gen 3 slot that you could drop a SATA card in if you really want to go big. A 10 second search turns up plenty of options that will turn that port into 10+ SATA ports for like $65. Dunno about the driver situation in that case though. The single M.2 slot would probably be used for the OS and maybe a cache. Having just 1 fast drive in an array usually isn't a win.