Hello and welcome to the forum.
Capacity of 3.86GB means the drive can't read anything from the platters and is displaying information based on the PCB.
This usually means that heads are gone unfortunately, or the drive is suffering from errors that won't let it read the Service Area. These drives are famous for such errors, so no surprise.
To answer your questions:
1. As said, these drives are prone to head damage, firmware errors and all sorts of goodies, so no it's not rare at all.
2. I'm afraid not. There are a couple of things you could try more, but please be aware that if your drive is suffering from mechanical damages (like bad heads), powering it up any longer can deem it unrecoverable. Having said that, and if you're willing to risk, you can power up the drive and listen to it carefully. If it's clicking and spins down after a while then 99% heads are gone. You could also find information about how to get terminal output from the drive (it's not difficult) and post it here. These drives have their terminal port locked, however they do spit some information upon power up. Again,
I would advise against powering up the drive anymore, if you care about the data3. Yes, a DR pro could be of assistance. No waste of money there and there are labs that follow a 'no data = no pay' policy, so you're good. I would suggest you contact Jon at
https://www.datasaversllc.com/ and they'll be able to help you at very reasonable prices. They're in Atlanta so you're very close to them.
4. Most likely yes.
5. Bad sectors can't be fixed per se. Bad sectors means the surface of the drive has gone bad and a healthy drive will re-allocate this sector to another place, if that is possible. Software like HDD Regenerator or Spinrite that claim to fix bad sectors (all they do is insist on reading them and if not, reallocate them) have been known to put nail on the coffin of unstable drives, for obvious reasons: You don't go about hammering a dying drive, it will just die and take your data with it.
To sum it up:
If your data is valuable, don't power up the drive anymore and contact a professional.
Best!