I have some issues with my parents although not as bad and similarly, I struggle to contextualise them - I feel the need to sort of have confirmed that some of the things they did were awful, but at the same time some of the things they did were unusually good so I feel a bit lost and then it all comes back down to "what is wrong with me?" which is where I get stuck.
this in particular rang a bell with me
"What most troubles me about my parents is that looking back I can see that slowly and surely they isolated us both - me and my brother that is - from 'normal' interactions. The clothes, making us stand out and eliciting bullying, Sunday School ditto (I know this was normal for some children in an earlier era but this was the 90s. Incidentally my parents didn't go to church themselves and weren't believers - well, my dad certainly wasn't; I think my mum was on the fence about it all.) They made it difficult for us to have and to keep friends. Didn't like us socialising outside the home at all really. "
My situation was similar except unlike you, I am pretty sure they did not do it on purpose. In fact my mother in particular was genuinely very attracted to nice, normal, popular young people and pretty clearly wondered why I wasn't like that but was a twisted ugly crazy dork. I was furious with her for cutting off all access to confidence and normality, and then blatantly preferring people who were normally dressed, had access to normal popular culture, were loved and supported and accepted, and were relaxed and confident around people of all ages as a result.
In adulthood I've found I don't have innate social problems. With a bit of confidence and thought, I've found that I can make relationships of most kinds work. But it's really working against my early conditioning which was to expect the world to give me a kicking and to slink out of sight as much as possible to avoid humiliation.
Do you have extended family members who might help you contextualise all this? I think you may benefit from talking this through with someone close but removed, who can see it all from the inside but from a different perspective. I am very lucky to have cousins who can really help with this.