One you recognize what is going on, isn’t it possible to give yourself what you need to break the cycle without your parents? For example, you become really aware of the thoughts you have and the emotional triggers you have and recognize where they come from. Basically give yourself the mirroring you never got. I could see how this doesn’t work if you don’t understand the mechanism you describe, but if you do, doesn’t it become possible? Maybe I’m too optimistic but it just does seem to me entirely possible to have that shift, and develop that kind of self reliance once you get how this works. From having been one of these adults, I can feel that when I validate myself in the way I never got (a combination of journaling and becoming ultra aware of my own thoughts and emotional triggers) and have perspective about why I was invalidated, there is a big shift in my body that takes place and I feel a huge warmth in my solar plexus. Sounds woo woo but it happens.