I love thinking about reconciliation scenarios, honestly. In part because I think some of the most interesting conflicts they could have would be post-staircase scene, and in part because the worst case scenario already happened in canon, so I love imagining if they made different choices.
In particular, if Curt makes a decision to stop running. Has some sort of resolve that he let Owen down once and it led to complete misery for the both of them, and he is determined not to let it happen again. And maybe it starts as a sense of guilt or obligation, maybe it's just a desperation to be with the man he thought he had lost forever, but the longer Owen is away from that protective shell he built up as the DMA, away from the character he performs to escape from his own pain, the more Curt starts to see just how much Owen suffered from the fall, and maybe starts to understand how Owen ended up the way he did.
I've written two post-canon Owen Lives fics, one that takes place right after the fall and one that takes place 17 years later, and they both center pretty heavily around Owen's disabilities. Both physical and mental/emotional. So there's chronic pain issues, joint replacements, burns covering his body, his own shame and internalized ableism over going from one of the world's greatest spies, at his physical and mental peak, to being severely injured and disfigured and attempting to recover while in Russian custody (before eventually being rescued from that situation by Chimera)
But I think with a fall like that, and the explosion, and the trauma of the man he loves leaving him for dead, he would also have a lot of mental health issues stemming from it. Periods of explosive anger triggered by seemingly small things. Severe PTSD. Paranoia. Cycling between keeping Curt at arms length, being vicious and cruel and lashing out, and intense fear that Curt is going to abandon him again. Flashbacks-- both to his time in a KGB prison and to what he did as the DMA. Times where he tries his hardest to hurt Curt enough to get him to leave, and times where he sobs and clings to Curt and begs him to stay.
I think pre-fall Owen was pretty buttoned up, that he loved Curt but was more reserved about it, didn't show his emotions very openly a lot of the time. But post fall, without his mask and the ability to live as a man without a name or history, he has emotional outbursts that scare him. Curt doesn't know who Owen is anymore, but his sense of self, his identity, was so damaged by the fall that Owen doesn't know who he is anymore either.
There's the question of whether or not Curt has the patience to actually be a caregiver for someone in such a bad physical and mental state, which is valid. But for me, I dunno, I could see Curt's stubbornness and his love for the man he knew winning out over his impulsivity and restlessness. I could see him being so desperate to make amends for the worst mistake in his life that he commits himself to caring for the man he loves, even if it's a miserable nightmare sometimes.
And maybe it's foolish and romantic and naive, but I like to believe that if they could manage to stay together, to keep going through the worst of it, they could someday (after a long, exhausting, intense journey) find some kind of healing together, some kind of peace