Hello Little Lion, and welcome to the group

You have a great question that is so, so relatable:
I am wondering if anyone successfully reconnected with their partner with BPD after that individual has worked on themselves? Or am I just being naive and holding onto something that will never be?
and it's clear you'd like your relationship to be healthier. So, first of all, kudos to you for being willing to work on yourself and your own issues. No matter what happens, that's a really positive investment in your balance and well-being.
Can I ask, how long have you two been estranged? Was there "a thing" that happened, or was it more gradual?
Here's some info about what to consider when hoping a pwPD (person with a personality disorder) will get help:
https://bpdfamily.com/content/how-to-get-borderline-into-therapyPlease let us know what you think after checking out the link and video.
I will say that the short answer to your question of whether a pwBPD will get help is, "it depends". So, it's not a No, yet it's not a given. I will also say that what the non-PD partner works on and changes can shift the tone and trajectory of a relationship.
Obviously there's a lot more to unpack, so let's start there...
-kells76