Notwendy and TelHill,
The golden rule really does not apply with these people. I promised myself that I will never get into a competition with a disordered person of who can treat the other person worse as a vendetta, though certainly I think those thoughts.

As for the moving out plan, I have started saving funds. . . . I’ve also taken the time to budget my monthly expenses and figure out what I can afford at the most at my current salary. It’s difficult but not entirely out of the question.

I saw my disordered neighbor today and she said "hello". I ignored her. Dr Ramani a well known expert on NPD, talks about how giving second chances over and over again does not work because the narcissist never accounts for their bad behaviors, act like they never happened, and then start being abusive again. I genuinely like to forget past problems with a person, and continue to be nice to them. Not going to do that again with this neighbor as she uses my forgiveness to restart the abuse cycle.

We often quote the instructions given at the start of every air flight... "In the event of an emergency, put on your own oxygen mask before attempting to aid others, and follow the attendants' directions."

We can't help others if we haven't first ensured our own safety.

That's just the reality, so we mustn't feel guilty about putting ourselves first in such scenarios.

P.S.

The pwBPD in my life shares that sort of thinking, which shows some narcissistic traits (on top of BPD).  I used to call it her "magical" thinking.  Granted, she's pretty, and that's a wonderful gift.  However, given her disordered BPD and narcissistic thinking, she believed she'd be "discovered" as a top model or top online influencer, and she dreamed of living a Carrie Bradshaw lifestyle.  She seemed entitled to it, as if she expected others to make her wildest dreams come true, for example by setting her up in a luxe apartment and paying for her travel abroad.  Thus she set herself up to be continuously disappointed.  The disappointment quickly turned to anger, even rage, directed at others who failed to make these dreams come true for her.  Most of all, she refused to take responsibility for herself.  This looks like blaming others for ruining her life.  She's constantly mad that she doesn't get what she wants.  Now she wants plastic surgeries to change her physical features, and she has asked her dad to pay for them.  At one point it sounded like she expected him to pay as compensation for making her look the way she did.  And the irony is, I think she's beautiful, she shouldn't change a thing, and even if she did, she still wouldn't be a model, not even close.  She doesn't have the personality(!), and she's far too old, short and heavy (in model terms) anyway.  Plus she couldn't handle the lifestyle, with all the rejection, critiques and stressful routines.  She seems oblivious to the actual work that famous people do.  It's the classic black-and-white thinking, where she idealizes the Princess life while disparaging the lives of "normal" people.  Does that ring any bells?

The narcissim manifests in some beguiling ways.  One example is during a job search.  The pwBPD in my life seems to think that certain jobs are beneath her.  She doesn't want to start at the bottom; she wants to skip a few rungs and get paid a lot, and yet she doesn't want a "stressful" job, either.  Her resume lists more aspirations and exaggerated roles than actual accomplishments and credentials.  In some regards she lied outright on her resume (for example saying she was a candidate for an advanced degree without having taken any classes yet, let alone be accepted into a program).  But I suspect that in her mind, if she wants something, it's the truth?  Or maybe she thinks, everyone lies on their resume, and she should, too?  Her online profile lists "moving to New York," but she hasn't done anything to move to New York yet.  Does this sound like your Sis?  I think it's the magical, narcissistic thinking coming through.  There's some identity confusion as well.