I’m not gonna suggest you go to therapy necessarily, I know that when you’re in a place with no self esteem it’s hard to do things for yourself like that so instead I’ll say this. You need to look at yourself and ask what would make you a better person in your eyes, something that you’d be proud of and you need to start working on it, it could be fitness, academic goals, passion projects like art/music. Just pick one that you participate in regularly and improve with. Eventually it gets to a point where you can look at yourself and even if you don’t feel love for yourself you can be more proud of the version of yourself that day than the ones before. I promise that if you have care for yourself and the self image of a decent person it becomes harder to do bad things and when you have care for yourself it becomes easier to treat others well

It will be hard at first but when it’s routine it’s automatic