You call it empathy, but it's just a symptom of being a parentified child.

Your mom didn't cut it, and you have developed into the best version of an adult you could be. Unfortunately, that comes at a high cost. I am eager for you to let go of your overdeveloped sense of responsibility and come to terms with your true role as the dependent one in this relationship. When you were younger, you were the dependent, 100%. You still are, to an extent.

Of course you want to have empathy and such- because it is very difficult to bear the full reality of the situation, but we outside, some who have been in very similar positions (I have) see the reality differently, and I might say, more realistically.

You've clearly gained a lot for your struggled, and I commend you for that. Your maturity, communication skills, empathy, sense of responsibility will all serve you well, but that doesn't mean your mother didn't screw up and deserves forgiveness when she has not done anything to earn it, it doesn't mean that you did anything wrong or villainous. It's a bit more black and white than you're seeing it (which is usually the opposite of what we'd say to someone on this board), and I say that not to criticize you, but in the passionate hope that you will relax, stop defending yourself against an ugly reality, and just feel your emotions, honor them, don't try to out think them, and heal.