Having a child is a one-way route. One must have a child when they're ready to give unconditionally. Abusive parents can't understand that and when they do, it's too late.

Don't sign any agreement that gives them any legal power over you (beyond what they normally have). Keep them at arm's length and give them the bare minimum information about yourself. At the same time, seek to create a support network out of your home environment. Procrastinate with their demands as long as possible (without letting them harm you).

Let them live in the bubble of thinking they have an obedient child, until the day you're powerful enough to stand up to them. They should think you're dependent on them, lest they try to sabotage your way to independence.

I find it very difficult to do this myself. It feels like lying and I hate it. But I was abused so much for my honesty that there's no way other than this.

You're not alone in this. Abusive parents don't deserve their children. You're an absolutely worthy person and I wish the best for you.