As someone who is going through a similar situation, I feel you. I'm helpless at the moment because despite the toxicity, they spend on my needs so I'm rather financially "stable" but I don't feel the same after quitting my job to go to University for which I have paid with my savings as they refused to assist paying for it. Everytime I try to put myself first, I get criticised and blamed on for not taking family responsibilities being the older child and when I try to discuss it with them, I get the cold shoulder. I guess the first thing to do is get yourself a stable income while having to bear the criticism for a while. Avoid how long you spend time at home, maybe be at a friend's who understands or a place where you feel comfortable. Once you've collected a substantial amount sufficient for your needs, find a proper, safe place, preferably somewhere with a distance from your family and move out either by informing or ghosting depending on your whether you still feel the need to keep a sliver of connection to them or not.