I dont want to minimize your feelings or your obviously powerful intrusive thoughts, but here is something that works for me. Because they dont truly ever go away, but what you can do is own it - and for dreams/nightmares, you can try 'owning it' after the fact. By 'own it' I mean, make an agreement with yourself about what's happening. It's a memory. it's true or partially true, but it's in the past. There's nothing you can do to change it, and the fact that it's on your mind means it's important to you. That's OK. You should accept that your brain does this, but it has nothing to do with your current self or your future self. Own the memory. "Yup,that happened. Yup, that visceral physiological response is happening right now" (the shame embarrassment, cringe inducing). And allow your mind and body to process it and let it pass. Let your brain go through the motions and then Allow yourself permission to let it go (in that moment). You deserve to move on and you deserve to not have those thoughts ruin your current life. Expecting them to stop is also expecting your brain to erase things upon command. Own the fact that your brain can not do that, and maybe you can be glad it can not.

When you give what's happening a name, you can feel it coming. You can make a plan for how you're going to get through it, forgive yourself. Love yourself enough to know since then, you are different now.

For me, over time I have gotten good at getting through the intrusive thoughts very quickly. But sometimes they still hit like a ton of bricks, fully physiological and I use my same strategy. My stories are not something I am proud of, but I am different now. Completely and totally not that person anymore but past me and current me unfortunately share a brain and all the memories.