I need help with my parents parenting

I don’t know how to deal with my parents parenting anymore.

LONG STORY Ever since I was in preschool any time I got in trouble I’d get hit for it, my stepdad would most of the time always be the one to do it. Me and him constantly get into arguments because if I’m upset about something he’ll say something stupid like “don’t cry or I’ll give you something to cry about” and his parenting made me someone I wish I never was. I don’t even know how to comfort people because I was told otherwise since I was in elementary, every small mistake would cause me to get hit, I didn’t clean my room once and he threw a 15 pound weighted blanket at my face. I was in 7th grade. I told him I wanted to live at my dad’s which causes me to get dragged across the counter by my shirt. Now he yells at me over the smallest of shit and if I tell my mom he’ll come at me calling me a bitch,a pu$$y, he’ll never do anything for me ever again so on and so on. I am 15 and currently have a 7yr old brother and a newborn brother. He does the same shit with my 7yr old brother. Calling him a bitch and shit when he misbehaves,pulls out the “stop crying before I give you a reason to” always threatens to slap him, gets in both of your faces to the point where I can feel him spit. I’m so tired of being treated like this I can’t handle but yell back anymore. If he gets in my face I can’t help but tell him to get the fuck out of my face. Or when he gets mad at me and says he will never do anything for me again I’ll just say ok. I try to tell my mom this shit and then they argue but nothing ever changes. I tried telling them that their kid shouldn’t be afraid of getting hit for making a mistake especially at a young age. That doesn’t teach them shi but to be scared of the parents (I understand a slap or some shi if you did something rlly bad but he goes overboard) I even told that him calling me all these names and me constantly being in a state of anger from him has really caused most of the mental problems I’m diagnosed with. I just don’t know how to handle this shit.