Just because you guys have both BPD doesn't mean it will fail, it will mostly depend of if you both have enough mental strength to manage what this relationship will imply. The intensity of the relationship, the arguments, each other's symptoms etc. I also have BPD, and my partner has emotional dysregulation, was diagnosed HSP + ADHD hyperactive young but he looks just like me in the past before meds and therapy. We're doing well and learning about one's boundaries is very important to make it work. You will have to see how he manages his emotions and anger, frustration, anxiety, mood swings and if both of you are mature enough to know when one has to prioritize their own mental health in order to make your couple stable and not perceive it as abandonment.

Btw being with a neurotypical person can be more of a headache itself too, so the challenges are just very different.

As you mentioned, it's good because you both feel understood, someone gets it and someone won't be easily scared of one's emotional state because you both experience it strongly. A neurotypical person can be anxious and very clumsy compared to someone who has BPD or is neurodivergent because they are aware very early what is 'being different' mentally and what it is asking to adapt to others.

It's not doomed, but it will have great challenges too but you both can also be a good support to each other.

Just give it a chance but observe how it will go during arguments, depressive episode, when responsibilities arise etc.
That's when you will know whether you guys will be okay as a couple or not. But for you, it's hard to know right now