Trauma is tough. Don't feel bad about still having trouble with it so much after it happened. It really doesn't go away on its own because, especially if it happens as a child, it gets engrained in our core. It has to be dealt with.

I've tried the writing a letter thing, but only with one of the people that wronged me (babysitter/neighbor). I sorta wrote it as how hurt I was and gradually turned it into a sort of "someone probably hurt you before, and that damaged you to a point you spread that hurt the same way," and forgiving him. I kept it a while until I "felt" it was a good time to rip it up. It felt good, yeah, and I no longer fantasize about going back to the scene and burning tf out of the place, but it wasn't a miracle fix for how that trauma is stored in my body. Although I'm learning I still hold a lot from the environment I grew up in in the houses too, so there's a chance it helped more with THAT trauma than I realize and what's left is abuse and neglect from my parents (and later on exes).

If it affects you significantly there's EMDR which is supposed to be really good if you can stick with it for a couple months to learn to translate trauma (which the body is "stuck" in and thinks there is still a threat) to the past.

For anyone affected by trauma, I recommend The Body Keeps the Score. I hated it when I first tried to read it, but second time around I went in with a more open mind and a more stable place and found it incredibly helpful. You learn about how trauma affects more than you'd think, how the brain is stuck in fight/flight/freeze, and ways to overcome it. Not just "yeah, therapy" but like top-down, medication, and bottom-up treatments which are things like building connections even if it's just with a therapist, neurofeedback, EMDR. Then things like yoga, martial arts, meditation, theatre, and music. Medication is pretty self-explanatory.