sorry to hear that James. It's hard trying to deal with your own stuff when you are in a bad environment.
It sounds like it would make anyone stressed, not just because of the PTSD! Also, like many families. groups find the most sensitive person to be the scapegoat instead of examining the root causes, looks like that condescension is providing that outlet for them.
I know I have no idea what it's like there for you so these are just general suggestions, that may be wide of the mark for you.
Can you make any changes to your boundaries or something that refuses this role and the impossible demands, and pushes stuff back where it belongs? Like sending the stress back to the idiots that created it? Horrible though it might be, is there any opportunity to use it to try something new? Sometimes I think it's uncanny how we end up replicating our traumatic family life in groups we're in - either through initial choice of something familiar, or later, our own behaviours and we become almost paralysed, walking the old familiar steps we learnt to do in a family. So staying with it sometimes can be very useful to learn to be different - even while it's hard and frustrating. I think we often try complaining or trying to point out what's wrong, and mostly other people don't listen. I've done tons of that and then it occurred to me that I was going to stop complaining and just take charge of how I behaved and I stopped doing something at work that I'd felt compelled to do. Quietly, no explanations, no show boating.
At first it felt very provocative and anxiety provoking and then I realised I was simply learning to hold a boundary and that generally I would never get support or permission to do this - I had to learn to do it myself, with my own permission, for myself, because setting a boundary often makes things harder for others. Of course they weren't going to run around and make it easier for me until I put my own foot down and said no - and then they had to listen. I've since seen how important that is generally, making my own choices and statements amidst disapproval but that that gets far more attention and changes more things around me than all the moaning and complaining I used to do (which was my lazy option as it was less scary than setting that boundary). More respect too - from me and them.
I find when something in the way I am changes then the situation at work starts looking, or even becoming, something a bit different. Even if we're not able to obviously influence things it's weird how often we can do just that , just by changing our steps in the game. We do have more power simply because we're part of the dynamic and much more than we think which is sometimes lost to us when we've grown up in a crazy situation we had no power over.
Am I reading you right that you're thinking of leaving and going on benefits? Just thinking that work - even bad work -does give you things that welfare doesn't - routine, company, a purpose, other stuff to think about, ( at least) and that maybe those things are worth preserving? And that being on benefits might bring up a whole raft of things you aren't feeling or worrying about now?
Just random thoughts.x