M vs : What's the Difference?

2 M key slots have five pins and support SATA, PCIe, and NVMe protocols They are typically used for high-speed SSDs and other high-performance peripherals

2 SSD Please refer to your motherboard documentation for details) Socket 3: SSD Drive Socket with SATA or up to four PCIe lanes

m24 slot Ultra-Fast PCIe Gen3 x4 with PCIe NVMe & SATA mode support; High Quality Solid Pin Power Connector 12 Connector for SSD 13 All Solid Capacitors

m2 slot I have a SATA SSD from Samsung and a motherboard from AliExpress The specifications tell me the slot's interface is NVMe,