As someone who's been in a similar position... you can't. I was extremely isolated and 'homeschooled' throughout my formative years. It appears to me that the feeling of alienation from peers is something most homeschooled children feel, and it doesn't seem to go away. Crushing depression and anxiety resulted in a type of self-isolation in my latter years, which my dysfunctional parents enabled to an irresponsible degree.

The knee-jerk response seems to be "seek therapy" or inane platitudes like "you can live life now!". They feel invalidating and trivialize our issues. On one hand it's understandable. Unless you've been through this sort of abuse it's probably impossible to accurately imagine its effects. On the other hand it's just really sad and frustrating.

We're missing a critical foundation. I don't know if that can be restored. Personally, I don't think it can. I'll tell you the things I thought might help, but I failed at: try to get an education and qualifications, as you'll have to work and these result in better opportunities. Try and socialize as much as you can. It will be difficult, and it will likely remain difficult, but you'll likely get better at masking with enough practice. Talk to therapists that specialize in CPTSD maybe. I don't really know... I'm struggling in similar circumstances, and I really haven't found anything that helps.