That sounds far more severe then "just" a Spider Wobble.
If this snake always had such a severe issue, it wouldn't have made it to that size. While a wobble "can" get worse or better over time, it usually doesn't change that dramatically.
A wobble is a neurological issue. The spider wobble on its own is usually not a bad one, either. It doesn't have to be "hell". I know of a dog with a neurological issue that causes it to constantly wobble its back end back and forth and it falls and "dances" all over the place, can't really walk straight. Yet, that is ONE happy, healthy, hyper little dog. It would be a travesty to put it down. A dog will clearly show you if in pain, with their eyes, body language even vocally.
A snake can't do that. But a snake that is "in hell" will not eat nor thrive. Most spiders live perfectly healthy lives and the ones I've come across were some of the best eaters and also some of the sweetest in personality. The one I had was simply a sweetheart and never a problem. I was lucky that she also had no cork screwing and only a occasional miss on striking the rodent. But even the more severe ones I've seen were NOTHING like what you describe.
Many diseases can cause these symptoms. Even certain fumes in the air (some almost undetectable to us) can cause these issues. Having bug treatments around the house (no smell to us) can cause these issues. Off gassing of certain paints, stains, glues and whatnot can cause these issues. IBD, other diseases can cause them.
This snake could have a viral or bacterial infection. It could have over heated at some point, which can also cause these symptoms.
If there are spiders that have SEVERE issues that keep them from living a normal life and thriving, they will most likely never even make it past the hatchling age. Again, never seen one where I would consider its quality of life nor recommend euthanasia. Btw there are many other morphs that come with genetic hickups. Some may even have issues that can't be seen on the outside. The very fact of them BEING morphs is already a genetic anomaly.
I would make sure you quarantine that animal strictly and a vet visit would be advisable. If its like you describe, that is not just a spider wobble. IMHO.