Hello. It sounds like you ahve toxic parents. No matter how much you want them to change, they will not change. They are who they are and they arent very nice people.
Yes, it appears that they have in fact failed you as parents. Thing is, they dont want to hear or think about that. They are more than likely wrapped up completely in themselves and what makes them feel good. On the other hand, they make you feel like crap. They blame everything bad on you and dont want to be educated or know about anything or any other way of seeing things.

Time to let go of this and go on with your life. Why expose yourself to this constant rejection and hurt? They will never get it. There isnt anything wrong with you. They are the ones with the problem-- and they will continue to make your life miserable and they will continue to disppoint you as long as you are there as their personal pincushion.

It is what it is and you would likely be happier and better off if you stayed away from them and take care of yourself and your won family and make your life as full and wonderful as possible. You are not emotionally crippled and toxic like them.

Stop now.
Think about what you have accomplsihed in spite of them. Give yourself credit for the kind of work you do and how you care about and help and treat children in way that your parents were never and are not capable of doing. You are a giver, kiddo.
The givers of the world make it better for everyone. Your kindness and caring is a gift you share naturally because of the kind of person you are. Your parents will never appreciate this. They will never see you as the good and accomplished person you are.

You are more grown up and together than your parents will ever be. Yes, you have anger and greif and regrets and a righteous sense of loss and rejection because your
parents are not who you need and want them to be, but they just dont get it and they dont get you. You on the other hand, need to amke the ahrd choice of taking care of your needs first-even if it means you have to stay away from these people.

Sometimes leaving family and moving on to live life on our own terms is the only way we can be free to work with our righteous anger in a healthy way and go on to be happy and secure in who we are living the values that are truly important to us.

Take care.