Sadly it sounds like the power logic internally of the drive needs repairs. You stated you have another exact same drive can you first get a new drive which is large enough to transfer your data to (I would get an SSD this time)
* So what you’ll do is first back up your currently working drive to the new drive
* Now carefully open the drive cases (both) keep track which is which!
* Take the working drive out of the case and put the non-working drive in
* Now before putting back together does the dead drive now work?
* If it does I would look at getting one more new drive (SSD) to then back it up.
Sadly drives fail, so its important to have multiple copies of your important stuff. I use a set of drives which I rotate and I even have one in a safely deposit box at a bank just in case something happens within my home. I also use cloud storage for my purchased media and when I travel light I use it for my general snaps from my phone.