One thing that may be a miscommunication... Speaking as someone with a comorbid disorder... PTSD isn't static. It's not like whatever level you're at, is what you'll be dealing with forever.
It took me a long time to wrap my head around that, as my other disorder IS static. There are 10,000 coping mechanisms, so it doesn't affect my life so severely, but the symptoms & expressions are here to stay. I just have to work my way around them.
So it's not like quadrupled anxiety & paralyzed nonfunctionality = your new normal forever that you will just have to work around.
PTSD symptoms WILL lessen over time. & Increase/Decrease in response to things. It's not a permanent thing, this level you've gotten to. It's just one of the levels PTSD goes to. That you may be hanging out there for awhile? Doesn't mean that you won't back off this level onto the level it was at before new trauma, nor that it won't back off to being virtually asymptomatic.
So that may be what your providers are talking about when they're saying it's impossible? If you're talking perm & they're saying THATS impossible?