I was forced to call emergency services and she became enraged, because she sees it as me betraying her or trying to get rid of her.
Yep. This is how they see it.
Here's my example: We have a lovely assisted living facility here. There is a waiting list of almost 300 people wanting to get into it, because it's such a great option!
My mom sees anyone (friends or family or health care workers) who speak with her about assisted living, as "wanting to stick her in a home to die".
My mom is 87, and has lost vision, hearing, mobility, and smell. She has multiple chronic and serious diseases (heart disease, strokes, Parkinson's etc), and is a huge fall risk. She is clinically frail. Suffers anxiety, depression, and uBPD. We think she eats ice cream 3 meals a day. Or crackers. She still lives independently in her home. She has cancelled home care she was receiving after falls and during recovery.
What I can say is that it took me a very long time to just accept her the way she is, and accept that I couldn't change her faulty thinking. The distorted perceptions of a pwBPD are a disease. We can't make that go away any more than we can make any other disease go away because there are no magic wands.
"Meet her where she's at", or you will bloody your own head banging it against the brick wall which is her.
Nothing you do will get her to snap out of her delusions. She has to find her own way out of her mind frame. Or get medical help. You can't solve this for her. I know it feels like she's probably make it your job to fix her, but it's not. She's an adult. If she's a risk to herself, or if she's having hallucinations or delusions, speak to a doctor. These are medical problems, not daughter problems.
You mention that you want to validate your mom without enabling her.

There's a really good section in this website that talks about "don't validate the invalid". Maybe you are already familiar with this, but if it sounds like something you might be interested in reading, you could type it into the BING search on this website. It will take you right to the article. I have read it many times over the years. Very helpful, and I seem to continue to benefit from rereading for reminders.
Out of curiousity, how old is your mom? Have you noticed any changes in her cognition? Sometimes as they age, they get more paranoid, but it sounds like your mom has plenty going on already without the aging factored in.
By the way, I've called the ambulance 3 times for my mom. She wails "I just want to die!" Her emotional disturbance is so very acute and outside of any range of "normal"... And yes, it's always bad that I call the ambulance, even though she's having an apparent heart attack (which turned out to be angina), or she's had a fall. She once had a fall under a plum tree, didn't admit to it until days later when she called me in pain, and I took her to the hospital to be checked out. I wasn't even at her house when she fell under that plum tree, but somehow the pain resulting from that fall was my fault. It came out in a terrifying rage directed at me.
I don't know how to stop being an enabler while still validating her feelings is what it boils down to. I've told her what she wants to hear multiple times, just to end the conversation. I know it's not a good strategy, but I have my own stresses to deal with and I can't deal with both mine and hers. I know she'll want me to bring her things at the hospital tomorrow, and I don't know how to speak with her when I know she'll bring things up. If anyone can give me any advice or wise words, I could use them.
Are you familiar with SET? (Support, empathy, truth)
You: Hi mom. How are things today?
If she's emotionally dysregulated still, distracting her with a gift (my mom likes ice cream cones) and conversation over simple neutral subjects would be my suggestion. Make the first one a short visit so it ends before it goes off the rails.
If you think her emotions are settling down, you could try SET.
Her: blah blah blah
It sounds like it's been very difficult for you. (support-you can give more specific details than "very difficult").
I can see you are frustrated mom. I think anybody in your situation would be frustrated. (Empathy)
The doctors say... (truth). I brought some things I thought you would like. Is there anything else I can bring to you?
The longer she stays in the hospital, the more likely the staff is to see her behavior and her delusions. That could be helpful for both of you.
You could also consider "confidentially" discussing any concerns you have with her doctor to give him/her your insights. If what you want to discuss is something you want to remain confidential, be sure to discuss the confidentiality piece first.
I'm kind of stabbing in the dark here with suggestions, so what some of us have done in the past is post concrete examples of what the pwBPD is doing/saying into the thread, and then other members suggest possible responses. It's worked well for a lot of us. There's so much experience and wisdom on this forum, and people willing to help. It's always easier to come up with good rational ideas when we're not the one in the eye of the hurricane. In that way we help each other.
Most importantly here, is to look after yourself. Your mom is being taken care of in the hospital. Are you finding ways to also look after your own well being during the chaos?