She is only 20 and from what you're saying she experienced throughout her life, she has so many more years to go until she could be fine. Her brain is still very young and there's many aspects she can't see yet that are gonna come out in the following years.

I definitely understand your frustrations with her reactions, she is definitely not at peace with so many things and my honest opinion is that you two are not good partners for each other because of big difference in life perception. Best wording I could do right now.

And the advice I'm giving is purely from personal experience. I'm 22 and have a ton of similar trauma behind me. I can say at 20 I wasn't aware of 90% that I'm aware of right now and I learned that the journey towards understanding and healing is way, way longer than it seemed. Having people who simply can't understand my situation would only make things worse, I suppose it's the same for everyone else.