Extra: it just came to my mind that whether or not Akiko is willing to stay with him (or how far she is willing to vouch for Kyou/help him) could be dependent on the amount of goods he does in the Redemption Arc. The only real check (available so far) is him using the Penlight or not on Akiko (breaking it is after everyone isolated him, so IDK if it really counts, especially because there is no option to help Hiroko through hypnosis) which aren't enough checks in my opinion, other checks could be making Hiroko forget (or heal faster), Kyou being 100% honest with Akiko (the dialogues implies that this are things he regrets, so it could be at least a choice) and Kyou (if he chooses to use the Penlight) only using it to help Akiko (either on her career or her trust issues), have safe fun with her or letting her use it as a sign of trust.
For example, if Kyou actually was honest with Akiko, uses the Penlight to have fun/help Akiko (another check if you will) but didn't heal Hiroko, then, if he falls back into escapism, Akiko pleads him to stop it and to not fall again into use the Penlight for evil (a potential final check on redemption) by trying to appeal to his desire to be a good person and her desire of him actually improving. But if he used the Penlight for evil again, then she is afraid of him. At the same time, if one falls and brainwashes her, then the checks shows how far she is willing to go to protect her brainwashing boyfriend (the more good checks done would lower the chances of Akiko trying to kill Rise) and if Kyou decides to not do it, then Akiko starts going with him (only if enough "good" checks were met) and encourages him to improve or try to become her therapist (either emotionally or professionally is another thing, perhaps based on said checks) and the final confrontation depends on how much is Kyou willing to improve, either by being given the benefit of the doubt (like by breaking the penlight) or then deciding to keep a watch on him or the group completely isolating Akiko with Kyou, again, based on checks of what Kyou did before to show he was willing to improve.
Another example: If Hiroko uses the Penlight and starts to be corrupted by its power, Kyou's actions becomes a check for Akiko (if she starts to turn Kyou into a puppet or test subject) to realize on how evil she was becoming and then heal him (whether or not Sayori, Nozomi, Hiroko and Rise are part of this is a different can of worms, but it would be an interesting moment to put Sayori and Akiko's friendship at a test if Kyou helped Akiko with her trust issues into not feeling low on herself and willing to try to make amends with Sayori) even if she is afraid Kyou not forgiving her or going back into darkness (another check) with a final check being breaking the Penlight.
Sorry, for the extra post, I just think that, for the redemption, there are many things that Kyou should/could do to prove that he has changed and Akiko's behavior (especially after he gets isolated) are a good way to measure how well Kyou did to improve, especially if Akiko is given a role to try to help him, either to be accepted by others or to heal him into loving himself (as in, wanting to be a better person and not let his previous actions define him) depending on what choices Kyou takes.
IDK, I think Akiko has a lot of potential depending on where she is used.
Side Note: a path where someone (like Rise's boyfriend) steals the Penlight would be interesting, would Kyou try to make another one just to level the field or would he manage to find a way to stop him without him? I won't push for this because I know it is already hard to even think how the only moments coming to mind are when Kyou (in one of Hiroko's route) or Nozomi (on dominant Nozomi route) throws the Penlight and the Penlight doesn't break and nobody thinks of looking for it.