Why does my 7yo brother hate me so much?

Hey guys, I don’t know where else to ask this, and I really need advice on where to go from here.

My little brother is 7 anddd there’s about a 10-year age gap between us. Having a little brother was one of my BIGGEST dreams. I was so excited that I used to research his monthly milestones, common concerns, what babies should be doing at different ages literally everything. When he was born, I always offered to feed him baby food, take him for walks, teach him things, i remember he was speech delayed so i taught him some sign , and id always play with him. I loved spending time with him.

Even as a baby, he seemed to favor my sister over me yk i tried not to read too much into it because he was literally a baby, but I genuinely don’t understand where I went wrong. He’s always been difficult with me, As a literal toddler he would ruin my things, he broke three of my devices, ripped up my homework all the time, and bit me. I know toddlers can be difficult, but he was and still is the polar opposite with my sister.

Now that he’s 7, things are getting completely out of hand. He doesn’t say this to anyone else and never would, but he calls me fat, stupid, and a nerd every single day. He’ll close my laptop while I’m doing important schoolwork, spit on me, call me “maid” every day, and expect me to do everything for him. He slaps and hits me daily for no reason. He also doesn’t respect my boundaries at all. He’ll say that listening to boundaries would mean having manners, and he doesn’t want to have manners. Thankfully, he isn’t like this with other kids or people, he’s actually rlly shy.

Nothing specific seems to trigger it even, It’s idk like constant, the whole day hes just calling me names, saying he wishes I wasn’t in the house, insulting me, and so on. He’ll even enter the room while I’m studying and scream so I can’t focus. I have serious exams coming up, and I genuinely cannot mess them up.

At the same time, he’ll claim he doesn’t know how to do things like brush his teeth or put on his shoes, just so he can tell me “Maid, come do it for me.”

The only thing I can think of is that I’ve been much busier with schoolwork lately. Maybe he’s angry because I don’t have as much time for him anymore? But everyone else is busy too, so I don’t understand why I seem to be the person he hates most. Honestly, this hurts so much, because I really cared and still do care about him.

is this normal? It’s getting to a point of affecting my studying and my friendships, I don’t know what to do from here. Do I completely ignore him when he acts like this? Is this like a phase? Is there something else going on with him that I’m missing? i love him, but I genuinely don’t know how to deal with this. I just need advice from people who have dealt with something similar. What am I supposed to do plss let me know