Would I be in the wrong for cutting them off and going lc?

Hey, so I've been making a couple of spontaneous posts about my parents and my home life for the last couple of months and I've gotten some advice, but not any good or helpful advice.

I really wanted to go onto Reddit and ask this question, as there are a lot of users constantly online, but recently people have been questioning the reality of some of the posts, and tbh I don't really want to go through that.

Also, it's okay if there's not a lot of responses here either, but please no hate.

So here's my issue: for the past year or so, my half sibling (I call him this because he refuses to see me as his sister after an argument where our adopted mother got involved and chewed him out) started acting like a literal ass to me. At first, it was him stomping behind me as I walked around the house, butting into convos that had nothing to do with him and saying he didn't like the topic of them, shooting me dirty glares, and making fun of my body and insecurities.

At first, my adopted parents tried everything that they could to make him stop, but no punishment or threat of taking stuff away made him stop. Recently, things kinda became too much, and I, a non-confrontational person ended up screaming at him, telling him to stop. The last couple of months were filled with him throwing himself around me, once again, butting into conversations that had nothing to do with him, calling me names, (like, big-girl, fag, and a bitch) and basically "stalking" around me whenever I leave my room.

I think I know what's making him act like this, but it had absolutely nothing to do with him and if anything, I have more the right to be upset. Two years ago, I made a friend online who was never really a "friend" to me. If anything, I loved him more than a friend, hell, I considered him my soulmate. Things happened before that where my half sibling got to know about him and told our adopted parents about him. When they learned about him, they snapped at me, because, "who in their right mind would make friends with a stranger online?"

They hated our relationship, and when something happened to my device that I was using to make contact with him with, they made me have no contact with him or any of my online friends for over a year before I got my internet access back.

I'm an introvert and tbh I struggle a lot with talking to ppl irl and forming emotional connections. They used that against me and just watched me spiral deeper into my depression. My adopted mother, a rather cruel person, (but I'd never tell her that to her face) would constantly make fun of me and always bring up at my doctor's appointments that I "shouldn't" be sleeping so much and that I'm "odd" for doing such.

But back to the topic, that year, I lost my friend and a literal week later, we took a trip to Canada where I wasn't "acting" like myself. That was due to me literally going into DKA and them literally stripping me of my access to my friend. But that trip was probably the worst trip of my life. Everytime I told them that something was wrong with my diabetes, they ignored me and chose to go on with their "happy" family trip.

I think it was an addition of both my emotional distress along with my bad health and them refusing to listen to me, but the day we went to my father's cousin's house, I exploded at my adopted parents and their bio child in the car. I told them that I wished I was dead and that another family, a family way worse off then them had adopted me rather than them. That they'd treat me like an actual human being and love me unconditionally no matter what I do.

That day, it was storming as my adopted parents shook their heads as they went inside and my "sister" and me had a screaming match in the car. I was literally sick, and they refused to listen to me, but all that was on their minds was the fact that I had an outburst at them on a sentimental family trip.

Two days went by, and I found myself becoming more and more sick. I was struggling to catch my breath, which in the end resulted in me struggling to breath, becoming dizzy whether I was moving or not, throwing up both food and liquids, and unable to hold full sentence conversations due to my hazy brain. Still, my adopted parents took my half sibling with them to go to a festival in Toronto Canada that day. Showing actions to the words that I said a couple of days ago, that they couldn't give less that a fuck about me compared to my "siblings."

When they came back, my adopted father took me to the emergency room where I basically almost passed out due to using excessive energy to just walk myself into the hospital. The hospital was furious on my behalf because who just lets their child suffer for almost a week in DKA before taking them in as soon as they showed serious signs of almost succumbing to said DKA. I passed out as soon as they pulled me into a room and inserted an IV in me, pumping me with water fluids. I stayed there for a whole two days, suffering with keeping fluids and food down, as well as not being able to feel much of my body and a sore throat due to throwing up the day they left with my half sibling and I swallowed my own acid.

It was one of the worst and scariest situations while I was in the hospital as I was often waking up just to black out again. This is also one of the reasons why I want to cut off contact with my adopted parents next year.

If you've made it this far in my yap session, thank you and I would like to know, would I be in the wrong to cut off my adopted parents, my half sibling and go lc (low-contact) with their bio child when I reach 18?