But you can turn this around to your advantage OP. You CAN build your own family of your newly made friends and your own wee family of your DH and DC.
Show your estranged family that you CAN do this life without them. Make THEM feel that you no longer need them. Most families thrive on being needed, and it can hurt them big time, when they realise that you no longer need them to be in your life. That is like a big slap in the face for them, and it's their wake-up call to realise that one less person in the family isn't dependent on them any more, for anything.
FWIW, I'm in the same boat as yourself. I'm being blamed for being the nasty one, when I absolutely was nothing but decent to all my family. I wasn't going to tell them about my impending move (not that I'd had time to even fart, never mind telling people unless I actually saw them whilst shopping), but decided to tell the one person who saw the dysfunctional behaviour of the rest of the family, and the only one I'd trusted.
Now I've moved 400 miles away and have basically shown them that I WILL do this adult thing by myself. I moved because I was doing what was best for my DC, and when I do the best thing for my kids, no-one else's opinion matters. I have to put my DC first at all times, and if it hurts people, then they really don't seem to understand what family is.
I've had my mum and younger brother saying that I'm not welcome in the family, that I won't see mum again before she dies and we won't be welcome at her funeral. When put in contrast with what the both of them had put me through emotionally and mentally, I can't, for the life of me, begin to really care about any of that. She sat and called me a bitch, prick and an idiot to my son, who did the right thing, got up and left, and told her exactly why.
Now she's playing the old "Woe is me, I'll never see my grandkids again" card. Well, she was never once, in the last 5 years, interested in them enough to even pick up the phone and asked how they were, so why would I think she's suddenly going to be interested in them now?
Do I regret moving? Absolutely not. Will I regret not making up with mum? Nope. I tried, but she just wouldn't open up about her issues with me, even though I encouraged her to do so, so that we could clear the air somewhat. She didn't open up about her supposed issues because if she even had any, it would mean facing up to the real person she was, as opposed to the person she still likes to portray herself to be.
So op, there's no doubt from what you've said that you can do this by yourself. There's no doubt that, if you've tried your best with them, been decent to them, been there for them etc, and they're treating you like crap, then your best bet is to stay estranged.
Being away from toxic people like your family, will be the making of you. Strive to be good to others. Strive to do the best for your DC regardless of what other people's opinion of you may be. Don't retaliate if they call you names, or berate you to others. A dignified silence can ensure that your estranged family will eventually show themselves up for the people they really are. And you don't have to do a thing. Let them sink themselves, while you walk away with your head high.