It Looks Like PCIe NVMe SSDs Require Bigger Slots

Two types of M2 SSD

ASUSTOR LOCKERSTOR 2 2 BAY WITH 2 SLOTS-image ASUSTOR Addlink S70 Lite 512GB SSD NVMe PCIe Gen3x4 Addlink S70 Lite 512GB

m2 pcie slot 2 slot doesn't guarantee NVMe compatibility was designed to support USB , SATA, and PCIe, and most early slots supported only SATA

m2 slot pc In contrast, SATA SSDs are either available in the form of the standard or the small and slimmer drives The form factor