How do I deal with such big family inequalities?

Based on what you have wrote, I'd say you have some growing up to do. If you are 20, you don't get a free ride until you think you want to move out. I'm amazed when young adults think that free rent ect. is a right. My kids know they are independent and while I would be a safe landing pad in case of emergency, the house isn't for their convenience after they get a job and start their life. I love my kids and hopefully your parents show that to you but you have to take control of your life.