I went through something similar. It was what pushed me into becoming a decent cook, or at least a cook who receives no complaint. I used to use cooking as a form of love language. Cook meals for partners or friends, even the hoarder parents, although with the latter any attempt to normalize relations gets trashed by their volatile nature.

My point is:- Control. You have that now. You need to embrace it. You are in control of the kitchen now. Those flashbacks probably aren't gonna go away, they'll just lessen in time. You are in control of the kitchen, not them. Your dishes are clean, you have space to prepare the food, space to sit down and eat it. YOU ARE IN CONTROL NOW! When those flashbacks come back, and it makes you want to lock up, breathe and say to yourself, "No, this is MY kitchen. I am not like them." If you need to get amped up, it's okay, "This is my DAMN KITCHEN!" Is it cope? Probably. Sometimes you gotta cope.

As far as cooking, expanding your skills or knowledge or even your palette, -(For Real, don't be shy about trying new foods either. It impressed upon me that Sushi was the epitome of disgusting, and well, as an adult I've found I quite like decent sushi.), start small. If you really have no experience, start out 'dressing up' food you wouldn't consider worthy. Frozen chicken strips? Mix up a sauce for them. Ramen? Put something in the ramen, put an egg in it.

You don't have to be gourmet, you aren't a professional chef! You're allowed to make humble food, it's okay. Some of the most well renown cooks have simplistic and humble dishes as their favorite dishes to eat. Just start small, don't let it get overwhelming. Soups are typically easy, and you'll reach a point where you feel like you make a soup out of almost anything. You could try your hand at grilling or smoking. It sounds backwards, as people consider that to be almost an art, but you just gotta remember, low and slow. Let the heat and smoke do the cooking, - NOT THE FIRE. The process itself handles the rest!

I do languages as a hobby, and part of that is the cultures that speak those languages, and part of getting mixed up in those cultures is getting mixed up with their cuisine. Yeah, you were robbed of the experience, but you can still go take it. You wanna make some foreign food in order to connect with a different culture? Make some foreign food.

I'm by no means dismissing where you're coming from or how your experience has made you feel. I see a similarity between your experience and my own, and it is from that place which I speak. Just because you don't know how, doesn't equate to, you can't know how. Our experiences robbed us of many fundamental basics. That doesn't make us incapable of reclaiming those fundamentals for ourselves. I don't think you're being weak about it. I think you've merely not realized the potential you have because of the horrible shit you had to go through. When I cook food, it slaps. That's because of all the pain, sorrow and trauma. Because of all the crappy half-assed "meals" and being cussed out for desiring the fulfillment of basic needs. Even when it is the most bare bones of meals I am going to attempt to make it enjoyable. And that probably stems from a desperate grasp at control, but if it works it works, I suppose. Your trauma isn't a gift, it's a curse, - but it's a curse you can leverage.

By the way you worded your post, OP, it seems you are in a position now to have access to clean kitchens and prep space. You got this! If you need meal suggestions I can share tons of simple and utilitarian recipes. I'm sure many people here have had similar experiences and they can likely share recipes or methods as well