You are doing more amazing summarizing and translating, and I am way behind in commenting and updating the translation communities. (Hopefully, I will start to get into the swing of the new teaching term soon and manage my time.)

My first impression of this scene is a little bit the opposite of yours, though maybe it will grow on me: Mirage is like that. It feels to me like Kagetora's attitude is coming from Kagetora in volume 25 or something. It's sort of, "Naoe, I'm so sorry for all I've contributed to what's gone wrong between us, but our love must find a way." And I'm glad they eventually get to that stage and glad they ultimately get beyond that stage, but it seems very strange to  see that stage so soon after Naoe has raped and impregnated the woman Kagetora loved, then forced him to be in her body while letting her die. The whole thing is horrifyingly terrible, very close to worst-possible-scenario terrible. This reasonably prompts statements like Kagetora's "I will never forgive you." And it makes every kind of sense that when Takaya begins to significantly regain Kagetora's memories in volume 8, his attitude is right back at "I'll never forgive you" -- ex. "Take your filthy hands off me" sort of thing. And it makes sense, and is very psychologically astute on Sensei's part, that by vol. 17, Kagetora is able to reflect that he was much (maybe more) to blame for what happened with Minako, that he goaded Naoe into it, that maybe he should beg Naoe's forgiveness. But to be at that point right after the events doesn't make psychological sense to me. And frankly, I think it cheapens Minako as a person and cheapens Kagetora's love for Minako and his own trauma, which is certainly equivalent to he himself being raped (and impregnated) by Naoe. (And I think it cheapens rape, in general, which is something Mirage is often on the edge of doing... I know, Japanese BL culture....)

At this point, I always figured, Kagetora's main motivation for coming back one more time was Kagekatsu/Miroku, that otherwise, he would simply say, "I'm done. I'm leaving this life," out sheer fatigue and trauma. To go straight to "I have to do this to make it up to Naoe," for me, actually cheapens Kagetora himself and the almost suicide-enducing struggles he has endured up to this point. It just doesn't feel like the right time in his psychological journey. (And it makes the Miroku plot kind of a second to his personal life when having to make personal sacrifices for the greater needs of the world is one of the main themes of the story. This also feels off.*)

All that said, I do want to reserve final judgment until/unless I can read the whole text myself in context and until I have some time to sit with this narrative and process how it might all fit (or how I might fit it in my head canon). The best explanation I can come up for at this point is that our characters in Mirage, like ourselves in real life, have recursive psychological patterns. There will be moments, for example, when Naoe thinks, "I have no right to be so terrible to him," and then he goes right back to being terrible. Or they will be in the upswing of their relationship, having great sex and talking about their eternal union, and then they'll start spatting again about how Naoe means nothing to Kagetora, etc. because thought processes and patterns don't happen wholesale; they happen in cycles and in waves. I suppose I could see this as an early wave in a thought process that will eventually become the dominant strain of Kagetora's attitude toward Naoe. I can make sense of that, but overall, it sits wrong.

But thank you very much for translating it. I hope they are able to do plays up to the end of this part of the saga, and maybe seeing it on stage will give me a different vantage point.

*And while I'm griping, a small older gripe. I used to think (given hazy summaries) that Kagetora came back because Kenshin told him he needed to look after Kagekatsu and didn't spell out the Miroku part at all (i.e. didn't really tell him why, just sort of said, "I need you to do this.") And honestly, I still wish it had gone down that way because it's damn good drama, putting Kagetora in the position of having drag out his last ounce of strength to once again protect the brother who had him murdered for no reason other than loyalty to Kenshin. I really like what that would say about Kagetora (healthy and unhealthy) as opposed to "I need you to come back one more time to basically help defend the world from apocalypse," which is psychologically a much less trying motivation. (Also makes me wonder about Kenshin's relationship with Kagekatsu. I've been getting the sense from these recent summaries that a lot of it boiled down to, "I needed to keep him close to keep an eye on Miroku," and again, it seems like it would be better drama if Kenshin really did love Kagekatsu and there really was that rivalry for fatherly affection between him and Kagetora on a deep level.) Okay, end of spilling out a lot of random thoughts. (Just to clarify, I do think Sensei is a bonafide literary genius. I am only being hard on her writing because my expectations of this story are about as high as for any story ever.)