My ASUS TUF motherboard does not read second SSD

2 drives are “keyed” at one end so as to prevent the end-user from inserting them in an incompatible socket PCIe NVMe drives are 'M' keyed SATA ones,

Do you want to know how to install and SSD on your Desktop PC motherboard? This is very

where is the gold slot Please see the picture of the 2nd slot, and the drive is simply floating out of the motherboard, only held by a metal plate in the inner side

where’s the gold slot Change your SATA mode from Intel RST to AHCI mode You don't seem to use Optane and this option is for RAID'ing your HDD with Optane drives You