Is there a SBC that can run entirely off PoE+ and that can take a couple SATA or M.2 drives?
Otherwise, there are dual NVMe HATs for the Raspberry Pi 5 but you'll be splitting a single PCIe Gen 2 lane across both drives (unless you go for the much more expensive HATs that have a Gen 3 PCIe switch on them to then share a single Gen 3 lane across them!)