Hi Gezin, welcome to the group

You're in the right place to connect with other parents and family members who have a loved one with BPD in their lives.
I think I hear behind your words how
hard you worked to help your D graduate from high school, and the hopes you had that maybe things would smooth out and be more normal for her with a "college and a job" life.
One of the things that strikes me as really challenging about BPD as a mental illness is how invisible, in a way, it is. I bet your D presents as "pretty normal" in many situations, it's not like she's necessarily "seeing things" or "hearing voices" or saying noticeably weird stuff, etc.
Because it impacts emotional regulation, not necessarily mental functioning, it can be hard to put together why our loved one, who seems so smart and capable, and who doesn't have an intellectual disability, seems unable to do stuff that would be normal for that age range. Why can't she hold down a job? Why can't she stay in school?
One way of looking at it is that the emotional dysregulation is so impactful that it "effectively" lowers the person's ability to do normal life tasks. While her "intellectual" wiring may be fine; i.e., there isn't necessarily a developmental disability or brain structure issue that acts as an upper limit to her capability, the intensity and frequency of her emotional dysregulation impinges on her ability to do normal things.
She may have some awareness of this, yet perhaps the shame of it is so great that she averts by making excuses. So you end up with the situation of -- she has some awareness of how she isn't able to do the "normal" things that peers are doing (living independently, holding down a job, going to college, having long term friendships...), but has a lot of shame around her shortcomings, and so comes up with reasons/excuses why "it isn't her fault" or "my boss hated me for no reason" etc. Anyway, that's just one way of looking at it.
So it's good that her treatment team may also see that and recognize that even though she's sort of been functional, she needs longer term, more intensive help.
And, weirdly, it might be not bad that she is looking for other jobs. Yes, she may run into the same issue, yet at the same time, it shows some motivation, and it gives her something to do as you all wait for inpatient space to open up. So again, that's another framing of it -- it would be nice if she actually held down a job, but if she can't, then maybe "success" for her looks like applying for jobs, going for a day, quitting, and trying again. It's a really, really different kind of "success" than we would want for our children, yet due to her emotional impairment, this may be the most "successful" she can be in this moment. Long term treatment may have some positive impact on raising her "success" threshold down the road.
I just feel so alone as I don't know anyone else whose child/partner/important person in their life has BPD. So I am looking for those out there to talk to, get support from and support as well.
That seems so connected to watching your D quit school and quit jobs. I wonder if it's hard to see friends/acquaintances with kids in that "young adult" age range who are holding down jobs, graduating from college, in stable relationships, living alone, etc. We really get it here, that kids wBPD aren't going to have "success markers" like other kids. pwBPD may have different trajectories and upper limits for emotional maturity, that show up a lot around "launch time". It's different, in a way, when your younger child lives at home, but when it's like "OK, you're 20, time for independence", many families here notice the emotional/maturity impairment a lot more: "my child does nothing but stay at home and play video games", "my child will not keep a normal job but deals pot instead", "my child is one class away from a college degree and it's been 3 years without finishing it". Basically, parenting a young adult child wBPD is so, so different from normal range parenting/launching. Again, please know you're in the right place to talk about your concerns, hurts, challenges, and story, without judgment like "well, just do tough love" or "if you set more rules this wouldn't have happened", for example.
The biggest takeaway for me here has been that dealing with any pwBPD in any relationship in our life is
counterintuitive. That's why we're here -- like you said, to be supported and provide support as we learn new, different tools and skills for navigating these
most challenging relationships where "normal" tools and skills just don't work.
Settle in, check out some links in the "Tools" tab at the top of the page, and whenever works for you (no pressure), keep us posted on how you and your family are doing.
-kells76