Think off the top of my head OP, maybe your DD should gap year then apply? If she can intern, volunteer or work FT for a year before college while working at home, it might solve two problems. It could give her something very substantive to put on her application. Especially if she can find something that relates to what she wants to do with er life. It could also give her an extra year and extra experience managing in the adult world while she is still living at home. It’s not a race. Maybe it takes her extra time.
Also, how about summers? I have a severe anxiety disorder, so I get the one step at a time idea, incremental progress. It might be easiest to start while she is not also dealing with school. Maybe she could find something without a lot of interpersonal contact, like shelving books at the local library. Or something at the school, where she is already comfortable? I’ve also seen this recommended for kids who like to write, but have social anxiety, ASD or are strong introverts.
http://www.writopialab.org/
Good luck! She’ll get there.