If SATA is what you want instead, it’s also pretty simple, just two diffpairs. At that, you can use either B-key or M-key, since overwhelming majority of SATA SSDs are B+M – here’s a board ...

For instance, a B+M key SATA SSD will not work in some NVMe-only M-key sockets, and some proprietary standards like CNVi throw a wrench into the “any M.2 WiFi card will work with your laptop ...