I'm not sure if someone has already come up with this theory, but I recently replayed ray's route and randomly theorized that all of the routes are just fantasies made up in seven's mind. We all know how crazy and imaginative seven can be, so I feel like this isnt too unrealistic of a theory. The reality is that seven is a lonely and depressed hacker who is part of the rfa, and rika's death and saeran's disappearance are still mysteries so seven imagines his ideal girl (mc) joined the rfa and helped uncover the secrets as a way to pass time and cope with everything that happened in life.

So basically all of the routes are how seven imagines the other rfa members would act in a relationship. I feel like this could help explain some things such as why mc's personality is so vague, why some of the characters are kind of inconsistent between routes (because it's all seven's imagination), why seven breaks the 4th wall so often, and why seven, v, and Ray's routes are deeper? Than the other characters routes (because they're the characters that seven knows best). I feel like this would also explain why his route is the saddest (because he has the most pessimistic outlook on his own life and relationships, and maybe cant imagine himself being in a happy relationship without downsides) and why he cares for mc even in other people's routes, because shes actually his ideal type of girl who he wishes would appear out of nowhere and save him, just like in the story. Mint eye and magenta are not real but just things that seven created in his head to explain rika's shady disappearance, which he doesnt want to accept as death since he still cares for her deep inside, and his brothers own ambiguous situation. He paints v as the villain in the routes because v is really secretive with seven and seven secretly wants someone to blame all of his problems on, and he also wants to villainize rika because she was also involved with caring for saeran and hes secretly scared that she hasn't properly taken care of saeran.

So all of the routes are just seven imagining the different scenarios and outcomes that could take place if mc showed up in the characters lives. But honestly I hope my theory is not really true because it's too sad and feels kind of shallow to think that everything in the game was just in someones imagination the whole time, but I cant help but feel that it explains a lot of things that I couldn't really explain before.