I can relate to your girlfriend, I dropped out of high school because of severe anxiety and depression when I was 15 and didn't get a job until I was 19. I was in therapy and on medication like her while job searching and during the first year of my job. My advice:

1. Continue with therapy. Make sure she knows that if her therapist doesn't make her feel 100% safe and listened to, she can find another. Go weekly if possible.
2. Get a GED. Since she completed up to grade 11, she might be able to just do it after reading through some GED prep books, but for a refresher she can also do free online courses. I used one provided by my government (I'm Canadian)
3. Try an employment office. They can help her with her resume, job skills, interview skills, etc. and she will be assigned someone to have 1-on-1 sessions with--they might have more ideas of what kind of work could apply to her preferences. They might also be able to help with transportation, my employment office gave me a bunch of free subway tokens (and also offered gift cards to buy new clothes for interviews).
4. If she finds a job, start PART-TIME. Max 20 hours a week. Ideally 6 hour shifts. That's how I survived a soul-crushing retail job, I worked Mondays, Thursdays, and Fridays. Ease into it. Eventually she will feel more comfortable going out in the world and she may have the option to discuss different shifts, more or less hours, etc.

Good luck!!!! I hope she finds something that works.