OP, sorry you are going through this. It is really hard! You and your daughter are not alone, as you can see.
I don’t have much to add other than maybe uncouple the farm from the internship. Doing one does not necessarily mean she has to do the other. I too think the farm could be helpful, although I realize it is a big worry for you. Here’s a quick story if this helps: Spring 2021, my D was in her last semester of college and breaking down (depression, anxiety). It got quite bad and I had to make a last minute trip to stay with her for a couple of weeks. She made it through, and continued with her plans for her summer job, which was at a performing arts camp about 8 hours away from home. No breaks to come home, barely any time off to even leave camp. It was super hard (due to covid staff shortages) but also helpful and healing, and I think why is because it was such a drastic change from her past 8 months: 1) it was a complete 180 from the stay-inside-finish-college-on-your-computer 2) outdoors 3)physical, with people face to face. It helped her immensely, and while she came home after 3.5 months very tired, she also was mentally healthier, no longer depressed, and could think about the future without spiraling. We were wary about her going, but also knew that sitting at home would not be helpful. She did get on AD about a month before she left, when I had to take that trip to college we put that into place, and that was part of it (she wasn’t reluctant, she was just in the depressive/can’t take any actions stage)…that we would feel better about letting her go if she was on medication.
Good luck!