Hi Shell Shocked, welcome back, though sorry why
From what I have read forcing into treatment may not work. Yesterday I read this article and listened to the video by Dr Cambridge was truly enlightening for me! I'd never heard of Anosognosia
https://bpdfamily.com/content/how-to-get-borderline-into-therapyMy daughter is 28 next week - she spiralled into crisis early last year, at which time she recognised the only way forward was to help herself through treatment, a painful lesson for her to learn - her way, she'd run out of options... .the good is she is now working hard to recover, never say never. She was able to complete her education and qualify ... .before crashing, though it was not a happy time for her.
I have found my daughter can't deal with too many options either (this became apparent over the last two years), she needs help in choosing her goal, keep it simple and provide positive support seems to be working. Present goal is recovery. I understand no treatment is often seen as an unacceptable option, of course we all want our children in treatment and recovery, for my daughter it came later and in her own time.
If your daughter can't/won't accept treatment at this point can you help her focus on one goal in order to stay home, either education or work inline with your September timeline? And yes to respect the family rules is as said, you have strong personal and family values and boundaries, they will help even if she pushes against, we stay strong.

If you have not seen have a look at Lollypop's journey with her 25yson who refuses treatment, self medicates. LP's using the skills learnt here to improve communication with her son, walk with him and be the best parent she can, she's allowed him that soft landing with a view to him living independently and being happy in the future, the ultimate goal. I recognise it maybe a jump from where you are, insights to everyone's journeys sure do help us. LP's journey is different to mine, the similarity is we are doing our best to understand our adult children, BPD using the resources here and looking after ourselves first. Not sure if LP agrees, thought I'd say we are both helping our adults 'centre' whether in treatment or not.
You're doing brilliant SS, yes it hurts and is confusing, what next you say? I'm glad you are here, I've learnt more here how to help my daughter than anywhere else. Over time, my daughter has matured, later than many, to accept her BPD and be responsible. I wish that for you too.
WDx