How can I make my parents see that their behaviour towards me has been abusive?

I (15f) have parents (42f,42m) who don’t have an ounce of respect for me or my privacy. In the recent years, they have stopped resorting to physical violence to get what they want because I stopped being responsive (It was primarily my mom who would hit me). In the past, my mom would hit me whenever things didn’t go her way, mostly when I didn’t meet her expectations. I was a bright kid, and would frequently score in the 90s, but she would absolutely flip out if I didn’t get all perfect scores. This would mean she would refuse to talk to me for a few days, making comments like “You don’t have a mother anymore, stop calling me Mom,” and telling me to shut up whenever I was crying after she beat me up. My dad generally ignored this behaviour, but took concern when my mom left a visible scar on me. He has also made comments about my crying, saying I was overreacting and things like, “She’s acting as if she’s Cinderella, as if we’re abusing her.”
This sort of thing lasted until I was 12, when I started being happy whenever they “disowned” me instead of being sad. How has this affected me? Various mental and physical health condition symptoms which my parents refuse to get checked, and I am very numb and disoriented in daily life. Also, I am failing every subject in school. Now, my parents don’t realise how toxic their behaviour used to be. They’re much better now, but still don’t respect my privacy at all (security cameras in all rooms, don’t allow me to read in my room) and are oblivious to how deeply their actions in the past have affected me. I wouldn’t feel safe directly telling them or anyone in real life any of this either. They’re mostly nice to me now but I still don’t know what to do. All my other relatives live overseas, and are generally conservative.
How can I make my parents see how badly their behaviour has affected me? How can I start gaining independence from them? If I were to go NC from them in the future, how should I go about it and how can I start making money without them knowing? (if they knew they’d instantly put a stop to it)

TL;DR: I am traumatised by my parents behaviour towards me when I was younger and they still don’t respect my privacy. I’m considering going NC.