My issue in that area was only that I was masking all of the time because I didn't know I was neurodivergent at all, just thought I was a bad person and had to hide it. It was when I figured it out and I asked them to accept me as I am that they left, saying I had been deceiving them all of those years and they wanted the masked me back because it was easier when I was making all of the sacrifices and accommodations.
If you already know you aren't the problem and dont try to hide who you are, then the problem of "deceiving" someone doesn't exist in the first place. If they accept you, then they accept the real you if that's all you give them.
I mean there are little social niceties and white lies and such that I try to accommodate for neurotypical people's needs even though they take effort, just like I ask that they accommodate my needs. All relationships, platonic or romantic, need to have some accommodations. But overall it's way less draining to accommodate them than to mask my entire personality for them and risking being abandoned when I can no longer afford the energy to mask entirely. And there are going to be times when we break down and can't accommodate their needs. As long as that's temporary, that's also part of a good relationship of any type.
We all have quirks and special needs. As long as both sides of the relationship put in a small amount of effort to meet in the middle when they have the energy to do so, and one person isn't required to make all the sacrifices, that's just what relationships are. I dont have BPD, but I do have some RSD (Rejection Sensitive Dysphoria). Accepting all of that helped me through some of the issues I have with RSD.
I'm definitely no psychologist or very good of a role model, but that's how I see things. And although it has taken a long time to get to where I am now, the journey has made me understand people better and I feel I'm a better person for it (not that we should have to suffer to be good people, just how the world often works).
I still have issues. I still have meltdowns. But when I have the "spoons" I help my friends, partners, etc., through their issues and they do the same for me if they can. When neither can, we just have the mutual understanding, through both having experienced spoon deficits, to accept that we're temporarily going to be at odds.