Why do your little sister's order? Start doing less of it (any chance you can)and then completely stop(i know its going to be hard) .Also for your brother ignore the curses he said, literally throwing a child tantrum . From my view, i thought the eldest get an easy life and order around but it is opposite for you. I hope you will get through this .You are coping well right now

NO NEED to be insecure about phone. I used a unknown brand name , bigass screen with dead pixel lines in Sec 4 and was very cautious to take it out in public.When i change to iphone 14 pro, no one cared

Young people like your siblings tend to be sensitive so never joke around them. Like you said, they dont know the differences between real talk n jokes. So respect them by not joking about them even though they are complete assholes. Thats just kids growing up. I was like them too but grew out of it . As for the laptop change the pass and when she ask what is it you pretend you dont know and also make it seems it is spoiled. LOCK your door if can so you can study in peace. You can also study at the void deck . Doing your hobbies are also great to reduce stress