Limerance and the twinflame idea are probably closely related in that there is something spiritual going on between people, its just that with limerance it may indeed be one sided. (Although i have my doubts)
I'm 95% sure it's all cognitive illusionry. What is happening in a limerance situation is that the brain is trying to fill in an affection/love hole with the love of God. This leads the person trapped in the limerance to believe that there is a spiritual connection between themselves and the other person, which the brain will use any circumstantial evidence available to reinforce. PTSD is a failure to handle reality - your brain cannot handle or interpret reality correctly, and my brain still mixes pieces of my reality up and connects them backwards and I have to untangle them to make them go forwards.
What is confusing is, apparently there is a love for God that allows one to remain a lifelong single, but if you're in limerance mode, you're "burning with passion" aka suffering from extreme lust, and God is not going to support your sin! The solution is to pursue marriage, to a healthy and stable marriage partner. Which is another can of worms, because many CPTSD sufferers do not know how to pursue affection properly, and then they end up in a cycle of abusive relationships. Fortunately, God can teach and model what a healthy relationship is, allowing you to escape the extreme attractions to abusers and break the cycle.
It's not just me that having a healthy relationship has worked for - I still remember the event at my community college where another woman stood up in front of the group and told us that her husband had saved her from her abuse. I was sorry to read the rest of your post and hear that you have not had much success. But the CPTSD sufferer has to want to break the cycle of limerance and be in a healthy relationship for the cycle to be stopped. Then they have to be willing to learn what a healthy relationship is and vet all their potential relationships for abuser signs and say no and bail out if there is any sign of it.
But I have digressed a bit. While I suffered from limerance, I actually was a bit "too smart" for it and would actually vet my limerantic relationships for abuser criteria, but I actually checked to see if there were any spiritual connections between me and the other side of the limerance. I took a "wait and see" approach, wondering what God would do. The answer was not really, all three times. (The reason for "wait and see" is fear of the relationship itself - I think that is what causes the functioning shutdown, because part of your brain sees the crush as a threat.)
For the first, the two of us were both Christians in a non-Christian and hostile environment to the Gospel. The result when I actually talked to the man was that he had massive insecurity issues and was an abuser. He was not the good ministry partner I had hoped. No spiritual connection.
The second was an unbeliever I was attempting to evangelize, which I did the wrong way. None of my poems ended up converting him, though I did end up exposing his own objectively evil girlfriend's behavior to everyone and end up driving her away from the school I attended. No real connection there. You can argue that learning poetry and graduating from college has improved my life, but I don't think so. I did pray for him, and maybe he will eventually accept the Gospel. Who knows?
The third was just wrong. We agreed on a debate moderation policy that a bunch of nervous empathic women disagreed with, in an attempt to spread the Gospel. That was it.
I did not have patience for a 4th one and was traumatized enough by the 3rd one that I concluded that my original goal of lifelong singleness was not going to work and I had a massive lust problem. I went to go find a healthy relationship and by God's grace I am now in one. Ironically, being in a healthy, real relationship has improved my life MORE than all three of these previous limerances combined.
I do think it is possible for a CPTSD sufferer to emerge out of their disease into a life of lifelong singleness; but that was not the path the Lord had laid out for me. Part of me still wants to solve the riddle of how that could occur, but solving the riddle will not change my life much, because even after getting rid of the limerance stuff and the cognitive illusions I still have a lust problem. My current boyfriend enjoys the fact that said lust problem is aimed at him. I'd honestly rather continue enjoying my relationship with him and just get married.
Anyway, this post is probably too long, but I do hope that it helps other limerance sufferers, past and present.