Hmm,
Sorry man, can you try the drive in another PC?
Do you have another drive you can use as a boot drive and see if it will appear as a secondary drive?
I would first try another drive in the place of the SSD, use the same cable and the same motherboard port.
If the new drive appears then it is a problem with the SSD, either the drive itself or some specific configuration.
If the new drive doesn't appear then try the new drive with a new cable and repeat with same MB port, if it appears then it is likely the cable.
If the new drive still doesn't appear then try the new drive with a new cable and a different motherboard port, if it appears the it is likely an issue with the port or port configuration.
If it still doesn't appear then, well then try the drive in another PC, if possible.
I know you've tried a lot of things but try it again is all I can say.