She grew up. Seriously. She's 21 now and was falling apart in 10th grade and fully fell apart at the start of Covid. She tried medications, therapies, appointments, meditation, special diets, etc. I kept saying "I think this is a phase - you need to wait for yourself." She was very quick to claim she'd tried things and they didn't work for her, and shot down all suggestions.
Now she's 21 and sleeping, eating and going to school. She will announce a problem and I ask if she just wants me to listen or make suggestions, and if she asks for suggestions she'll take them now. She quit social media around 16 and is poking her toe back in gently now because she feels cut off from society. So we've had some talks about healthy accounts to follow, and how much time to spend, etc.