something these guides indirectly touch on but don't explain more explicitly: frequently issues with socializing are rooted in trauma, and working on that trauma is what's going to fundamentally improve socialization. and for those unfamiliar, trauma isn't always "this one bad thing happened this one time, or many times". trauma is sometimes a lifelong pattern of small interactions, or lack of small interactions. childhood emotional neglect is sometimes impossible to even see from the outside, but can have lifelong implications to attachment styles that then later massively impact one's social anxiety and ability to socialize
also autism