I don't want to speak with some of my family members ever again
I am sorry to hear you are feeling this way. Why do you hate your family?
They always meddle into my life and they're also demanding.
Not everyone is born with a perfect family, and that's okay. You are an adult now and can keep whomever you want into your life. Just because they're family doesn't mean they'll be non-toxic, and for the sake of your health you need to remove all toxicity like that.
I can't do that. I don't have the energy or motivation to do that. My relatives are too demanding.
I think it is normal to find some people unpleasant to be around. You do need to learn how to tolerate those that are family.