That link tells you to format if it's recognized but not partitioned! while it's true you can recover after a format it's not as straightforward. And if it suddenly lost it's partition then the drive is obviously in bad shape. I would check disk management to see if it shows there but would not initiate a format.
Assuming you've tried different cables? I just had the cable for one of my passports die.
Does the drive seem to spin up? You should be able to feel it and tell.
Unfortunately the passports can not just be removed from the enclosure and used in a dock. The reason is the usb connection is actually soldered to the sata connection on the drive.
As far as recovery if the drive does not show anywhere (explorer or disk management) software recovery is not going to work. You will need to send it to a recovery specialist. Price can be cheaper than you expect but could be very high. I've referred a number of folks here:
https://www.recoveryforce.com/pricing/Note pricing is in Canadian $.