No, I didn't get that far in therapy. My journey getting there took me 15 years and only then was I able to go into therapy. I've been in therapy only since about a year, I entered because of anxiety and panic attacks.
The first therapist wasn't a good fit at all. I told her about the anger and she just tried very much not to judge me. She was very unsure how to approach it, and sometimes she did, and sometimes she didn't. I wasn't myself with her, as I felt her need for me to be a certain way. So, as usual, I followed along that path, but my anger towards her grew. Simultaneously, my anxiety got better, which sounds cool, but really isn't. We ended things when I no longer had anything to say to her and she might have thought that my anxiety was gone. I don't thing she noticed the anger I held towards her. She said I could come back, but after leaving I realized that I had gone down the path lined with anger and rage further than I had been in years. Needless to say I didn't go back.
My T now, I've been with him since end of last year. When I told him about the anger, he asked if it was directed at someone specific, or, jokingly, at random people. Now, xT was an outlier. Usually, my anger isn't directed at the people that cause it, but at random people. He understood, as do I, that that is the opposite of good. Next session he started by saying he wasn't sure he could work with me. I told him (as I had before) that his need for safety was paramount. That I understood it and didn't doubt for one moment that it was more important than anything. I also assured him that my anger is mostly directed against women, that even if my related phantasies would turn on him, it would never reach the same level (which is true).
He agreed to work for me for 12 sessions, making no attempt to hide his insecurity and making no promises to keep me on after. By his wish, I created 3 rating scales, 1 for anxiety, 1 for social connections and 1 for violent phantasies. I fill them out each day. I also journal each day for 30min before filling them out.
Once, when I reached the highest point till than (and to date) on the 3rd scale, he asked to read what I had jounaled. I had my journal with me and I reluctantly gave it to him. He took it, started reading, looked back up and asked if I was comfortable with him reading it. I aswered I was increadibly uncomfortable with him reading it but would ask him to ignore that and read it anyway. He went back to reading it.
So if you ask about me being vulnerable in therapy, that is a good example. Note my emotions more or less screemed at me to not go there, to not hand him the journal, to not let him read it. They did that in the room, they did that while writing the journal entry and while adding the rating to the scale. They did that from the point I had added the rating all the way to the session. My point is that I chose vulnerabilty every step of the way, but I completely understand not wanting to go there.
There are things I haven't shared, but not very many. I had a memory recently of an event in my childhood that hints at sexual trauma hiding somewhere in the deep, far beneath the waves of rage, anger, and, recently, fear. I have not told him that, because I am too scared of it. If I say it, it makes it true. If I tell him, he might hate my sister. I am not ready for that. And that's okay, there is time.
He has since agreed to stick with me. He asks fairly frequently if I like being there, coming to his office and talking to him. At the beginning, he wanted me to want to have sex with him, making sure to point out that he did not actually want to have sex with me. He seemed to tie me wanting to have sex with him to him being able to work with me. I understand it as him wanting to ensure strong positive feelings of transferance from me towards him, ensuring that the strong negative feelings of transferance I had developed towards xT were out of the question.
One session, he asked point blank, if I had yet imagined having sex with him. I told him no, we had kissed and he had held me, but that was as far as my imagination had gone. He seemed a bit frustrated, so I told him that he didn't understand what he was asking and that I would explain it to him. That was another very vulnerable situation to me, but I needed him to understand and so I explained without looking at him. I told him that my sexual phantasies too, had a violent component and I didn't want to go there with him. He asked which part I played in them and I told him I was the woman, i.e. the non-violent part. I told him I think his wanting me to want to have sex with him wasn't about sex at all, it was about me feeling intimate with him, but my sexual phantasies are not about intamacy. In fact they are dehumanizing and I did not think that he wanted that and I for sure did not want to go there with him. He understood. He has dropped me wanting to have sex with him since.
So these are examples of me being vulnerable that increased his understanding and bettered our relationship. That is the pro side of vulnerability.

Yeah, that's Probably part of the reason why I didn't enter therapy all those years ago. Though them locking me up and throwing away the key was my main concern, tbh.

I go through the pain now. The pain is a part of my day. I brought myself to this point over the course of that 15 years, because I was fighting the anger and the rage, the phantasies and the impulses. It's a good thing, really. And it's partly okay, as I am not completely pain-averse, though I don't have a history of self harm. It's a bit much though, this constant pain and anxiety. The knowledge that I could get rid of the pain and the anxiety if I went down the anger path just a little bit doesn't help, either.
I am in my mid-30s, so I have time to heal, but also time to digress. I am in limbo now, I passed the crossroads between anger and pain, choosing pain. I can still look back and see the crossing, I can walk back to it and switch paths.
I need to not do that. But I can't keep feeling this pain. So I have to work through it. But I don't know how to do that and I am worried my rage will come back. I don't think I can go through the process of getting rid of it again. 15 years, I cannot do that again. So it's a risk, all of it, and not just to me. So I need help to work through the pain and I need some people to know about me, in case I turn and make the wrong choice. I told T as much. It's quite a thing to ask of him, to be a guide and if push comes to shove, my prosecutor and prisoner.

All that aside, it also does happen in session. When I am vulnerable, he does reassure me. Once, he took me out of it. Sometimes, he keeps me there, asking questions which I answer without eye contact (though I have recently started glancing at him). We so far had sessions every 2 weeks. He is on vacation now (for a month) and when he is back, we will switch to weekly sessions soon after. Every 2 weeks has been good to give me time to process, every week will be something I and we need to find a new balance for. I have already written him a letter in case it gets too much, to ask for the old schedule back. I might give it to him if that arises.
Twice so far, I have lashed out at him. Little things, a word, a phrase, a tone of voice. I fall silent after, trying to find that void within, which removes me from my anger and as a side effect, removes all other emotions, too. The first time he asked what I was tinking. I told him I thought my reaction was unreasonably and uncharacteristically strong. Him asking the right questions and him not demanding I feel, but accepting my feelings as they arise slowly help to increase my level of comfort with him. He has stopped asking what I feel, he is now asking what I think, once removed from feeling.
I think his attitude would shift if my anger turned against him. I think he would drop me like a hot potato. But I also think that's fair. He needs to protect himself and for me it is important to control my anger and to let him see it, so if it ever comes to that, he can make the right choice, drop me or institutionalize me or whatever. And that's okay, I would hate being locked up, but if it ever comes to that, so be it. Life isn't just about me and I am thankfully not a narcisist (though my anger is a narcissistic defense).

It does help, thank you
I have recently come to the conclusion that I really don't know where my anger comes from. I know what cause it to resurface, but I don't think I know of it's origin. Still waiting for someone to validate it.

I'll answer to the rest of your post in a seperate post.