12-13-2020, 08:06 PM
I suspect that your Mac booted to Internet Recovery. If the SSD didn't show up at all in the DU, that suggests a bad drive-cable.
I'd remove the SSD and see if I could get it to show up as an external on another Mac, run a SMART check on it and then Disk First Aid to see if there's anything obviously wrong with it.
I'd remove the SSD and see if I could get it to show up as an external on another Mac, run a SMART check on it and then Disk First Aid to see if there's anything obviously wrong with it.